Misfire Cylinder 3 And 4

the misfire could be the flywheel, BUT it could be a million other things too check the plug on that cyl, move that coil pack to a different cyl see if the misfire code comes back but that cyl, or it could be a burned valve, though not as common on 03s it still happens. So they took the engine apart and replaced the burnt valve, put it back together. 2004 Ford Expedition Cylinder 4 Misfire code p0305 cylinder 5 five misfire detected cts cts v faq cadillac 1600 x 1200 · 123 kB · jpeg Source Misfire On Cylinder 6 300C SRT8 p0306 misfire at idle, please help - Chrysler 300C Forum: 300C & SRT8 968 x 959 · 394 kB · jpeg Source. Engine misfires, rough idle, poor performance, reduced fuel economy and engine misfire codes on 2004 to 2006 Pacifica (CS) and 2005 to 2006 Chrysler 300, Magnum and Charger (LX) models with the 3. afterwards the engine started to run really rough. The check engine light was on and flashing at times and the computer had a pending P0301 cylinder one misfire code. If the same cylinders 3 and 4 are still misfiring, then there could be a burned valve. I replaced injector web,replaced plug wire. 2 Ohms - 1&3 terminals 1. 6L engine has been extended to 10 years or 150,000 miles (whichever occurs first) from the vehicle's In-Service Date. From cold and hot. i cleaned the injectors but still the problem is there. For instance at idle. So "A" is 1, "B" is 2, "C" is 3. C is number 3 cylinder. Well they found a valve that was burned. misfire on number 2 cylinder, 2002 dodge ram 4. I'm strongly assuming it's the coil packs, as the problem is intermittent. The diagnosis was cylinder 3 misfire, an apparent Honda problem and one that I've had fixed once before on this same car at the dealership where I bought the car. after I did that the light when off. I have a problem with my bmw x5 e53 05 4. I have replaced all the spark plugs and coil packs. ok so i have done research for everyone thats about to say look up the topic lol it all started when i pulled my injector connectors to clean some corrosion off of them , ever since then its been misfiring, and this is what ive done so far but its still misfiring? and its a bad misfire. I replaced the coil pack, spark plugs, spark plug wires, fuel filter, checked the compression, checked the timing, and added fuel system cleaner and so far no results. Just as a regular misfire in cylinders 3 & 4 can be caused by a bad 3-4 coil, it could also be caused by a failing 3-4 ignitor circuit. Will not pass the emissions tests. 8L misfire? Does cylinder #8 have compression (compression test)? If not, perform a cylinder leak-down test to determine why. i was washing the vehicle, cleaning under the hood. I received 2 codes, P0304 - Cylinder 4 Misfire detected and P0316 - Misfire detected 1st 1000 revs. P0300 Random Cylinder Misfire. the codes were p303 and p1399. This time I changed the spark plugs. It developed a serious misfire with a Flashing Check Engine Light. MacFadyen on topic 2009 Subaru Legacy Cyl 3&4 Misfire @ 4,000 rpm Firing order is 1-3-2-4 so 3 & 4 are 360 crank degrees apart but on different banks. Ran fine yesterday, drove all over town with no problems. A misfire could be sending unburnt gas to the exhaust, which is bad for the catalytic converter (I don't know which is bank B). Hey everyone took the nitro in yesterday and got it back today. The story from the mechanic it is that due to some carbon build up and it has caused the valve guides to go bad. November 9, 2010. I checked 1 and 3 and 2 and 4 cylinders. I'm getting misfire codes on all 4 cylinders. 3 with AFM that was NOT caused by a stuck value, collapsed lifter, bad lifter solenoid or flat spots on the #4 cam lobes? I have an obvious misfire at idle which makes the engine stumble about every two seconds and I notice a slight RPM fluctuation on the tach. It won't rev over 3000 rpm and it gets worse when the transmission is in drive. Having a a major dilema with a rough idle / Multiple Cylinder Misfire on my 2001 Chevy S10. maybe every 3 0r 4 weeks to 6 weeks apart, Then started getting it everytime i accelerated a little more than usual or going up an incline for a decent amount of time. Found #3 & #5 cylinders to have misfires. After 600 miles it returned. It would run with a slight miss but was not noticeable at hwy. It runs rough at idle, particularly if it gets hotter. The DME is sometimes also called the ECU (Engine Control Unit) or ECM (Engine Control Module). Here are the four different types of misfire and how to diagnose them: Ignition Misfire. P0303 should not be ignored, and can be a threat to the drivability the Ford Ranger. I also swapped my new #3 wire with my old #4 one. As you may already know, each cylinder needs 3 very specific things to produce power and they are: Air; Fuel; Spark; If any one of these components is missing, in any one engine cylinder, your 4. The engine idles a little rough and the cel is on. The car starts fine. A misfire could be sending unburnt gas to the exhaust, which is bad for the catalytic converter (I don't know which is bank B). Has anyone experienced a P0304 (cylinder 4 misfire) DTC on 5. At speeds of 60MPH or 70MPH I notice my engine light started to blink several times, until it stop and staid on. Also, when dark, try misting water on the coil pack while the motor is running and see if this arc's or gives you the misfire. I pulled over to check out the engine and the entire engine was shaking. So last night as I was driving on break, I was passing this car and in 4th gear blew past him (~85-90ish). 8L misfire? Does cylinder #8 have compression (compression test)? If not, perform a cylinder leak-down test to determine why. A misfiring cylinder in a four-cylinder engine is, pardon the pun, hard to miss. I have a misfire that cannot be diagnosed!!!! 1999 5. It runs rough at idle, particularly if it gets hotter. That said with a misfire a good place to start is with a power balance test as shown in the video above. Did a compression test on cylinder number 2, showed 150 PSI. Honda Engine Misfire Settlement Class Eligibility : Purchasers of Honda vehicles with a V6 engine with Variable Cylinder Management (VCM-2) in the following types of Honda vehicles:. 2 TSI Auto on a 12 plate. Tahoe & Suburban DIY and Useful Threads - #4 Cylinder Misfire - I have a misfire on the #4 cylinder, I have changed the Spark Plugs, The Plug Wires, The Rotor & Distributor Cap. It would run with a slight miss but was not noticeable at hwy. Initially there was no OBD-II code but it got progressively worse and eventually there was a P0304 code indicating a misfile in cylinder 4. Have a 97 tj with just over 23700 miles the other day my computer threw a 304 code for the cylinder 4 misfire the plugs wires cap and rotor plus the. Theoretically there are two things required for combustion: Spark and Air/Fuel mixture. So if you. 2 Faults Found: 6352 - Cylinder 3 P0303 00 [237] - Misfire Detected MIL ON - Confirmed - Tested Since Memory Clear Freeze Frame: Fault Stat. Once it warms up it is back to just running a little rough. Hi, I just purchased a 08 T&C 3. Having a a major dilema with a rough idle / Multiple Cylinder Misfire on my 2001 Chevy S10. So I had the code read today and it still shows the cyl 7 misfire, but now also shows a lean bank 1 code. Since then, the car has been registering codes 300, 301 & 304 (misfire in cylinder 1 & 4 and random misfire). You can swap #1 & #3 injector, if the misfire moves to #1 then you know the injector is bad/dirty. 5 Camry LE with 74k on it. I decided to clear the code and then I restarted the truck and again it ran fine. Any ideas??. A 2002 Ford Explorer 4. We took it to the shop (not a Jeep dealership) and they tried switching the coils around and they said the codes kept changing. I opted to do this at home so I picked up a coil and plugs and planned to replace over the weekend. I'm strongly assuming it's the coil packs, as the problem is intermittent. I put my diagnostic tool on it and it gave me a P0303 code. It would run with a slight miss but was not noticeable at hwy. then i noticed that THE TIP WAS MISSING?!!??!?!?! Missing tip:. prob just goin to get the high flow cat anyways but need to fix. Here are the four different types of misfire and how to diagnose them: Ignition Misfire. Hello all! I have a 2000 4. It is driveable and intermittent misfiring but I don't like to tempt fate here and not pushing it. 4,5,6 front to back. PO 304 Cylinder 4 Misfire Was going to replace the sparkplug, but which is cylinder 4?! And any other suggestions for this CEL? update: bought new Iridium sparkplugs (same as old ones). Tahoe & Suburban DIY and Useful Threads - #4 Cylinder Misfire - I have a misfire on the #4 cylinder, I have changed the Spark Plugs, The Plug Wires, The Rotor & Distributor Cap. to isolate the root cause of the misfire. Cyl 3 & 4 is the same coil of the coil pack. There are several possible causes of misfire ranging from worn spark plug to faulty coils. 5L and today she threw the code P0303 which is cylinder 3 misfire. It just seems a little odd that all 4 are misfiring. So far I've replaced all the plugs, plug wires, new fuel filter, and new coil pack and injector in the number 4 cylinder. - Here's the story. Cylinder 3 and 4 misfire Was driving the other day, going about 35-45 miles per hour when my check engine light - Kia 2006 Rio question. But when I did a few 1/4 mile runs a few weeks ago the fuel cut out and the check engine light flashed. Random/Multiple Cylinder Misfire Detected What does that mean? Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly. 2L 318, random all cylinder misfire. A new coil module and spark plugs were fitted to no avail, the cylinder head was removed and the valve seats were cut and lapped in. Replied by Andy. Perhaps the most costly misfire malfunction to correct is the mechanical misfire. At speeds of 60MPH or 70MPH I notice my engine light started to blink several times, until it stop and staid on. The engine idles a little rough and the cel is on. I even went old school and removed the plugs on cylinder 3 and fire the engine. I have a 1999 s10 4. Honda Engine Misfire Settlement Class Eligibility : Purchasers of Honda vehicles with a V6 engine with Variable Cylinder Management (VCM-2) in the following types of Honda vehicles:. As you may already know, each cylinder needs 3 very specific things to produce power and they are: Air; Fuel; Spark; If any one of these components is missing, in any one engine cylinder, your 4. i had this problem with my 2003 sunfire 2. I replaced injector web,replaced plug wire. I am getting 3 confirmed cylinder misfiires (P0301,P0303,P0304) and random misfire (P0300). So far I've replaced all the plugs, plug wires, new fuel filter, and new coil pack and injector in the number 4 cylinder. The ECM counts the number of times the engine speed change rate indicates that misfire has occurred. And this is what caused a cylinder misfire issue. Timing belt, water pump, thermostat, o-rings, tensioner, pulley, valve cover. Used some carb cleaner stuff and sprayed around each injector and cylinder 4's injector seal has a slight leak. The car has a rough idle when at a stop light, but other than that it runs fine. Found that plug from cyl #3's electrode was completely worn down to a nub. The misfire is showing for cylinder 6, so I would go systematically and change the plug and recheck. The obd2 code showed a misfire in the #4 cylinder (P0304 I think). kronosperformance. maybe every 3 0r 4 weeks to 6 weeks apart, Then started getting it everytime i accelerated a little more than usual or going up an incline for a decent amount of time. Upon further investigation I found the # 4 cylinder is not firing. Soon as load applied smooth, and powerful. PO303 Cylinder 3 Misfire Code Discussion in 'General Discussion' started by rifleman625, Jul 13, 2010. Possible Causes:. Random Misfire, and cylinders 2,4,6 misfire. Any idea what it might be? a vacuum leak should create a random cylinder misfire right? Could the injector just be dying?. Its throwing a p0135 heater. i cleaned the injectors but still the problem is there. Hello, About 6 months ago I bought my used Subaru Outback at 130,000 miles. The engine light was on and said P0303 for a Cylinder 3 Misfire Detected. i read about misfires some time ago however this has just started. Happened as I was rolling up to a stop sign not even accelerating. Lack of power. prob just goin to get the high flow cat anyways but need to fix. Cylinder 3 and 4 Misfire I have had my outback for about a year now and have had struggles with cylinders misfiring for the entirety of that time. I went ahead and cleared the codes to reset CEL. P0304 Tech Notes The P0304 code means that the cylinder 4 is misfiring or is randomly misfiring. I have already replaced both plugs and wires. 100,000 miles and code just came on. kronosperformance. The scan tool showed the following 4 codes stored: P0300-Random/Multiple Cylinder Misfire Detected; P0301-Cylinder 1 Misfire Detected; P0303-Cylinder 3 Misfire Detected and P0305-Cylinder 5 Misfire Detected. I have a 2002 chevy prizm its misfiring in 3 and 4, when the engine is cold its really bad in gear, but when it warms up it seems to go away, i changed the plugs and when i took out the plugs for 3 and 4 they had alittle bit of white on the end of both of them. But less than a week later, same 3 and 4 misfire. As for a misfire, electrical wise the following could be at fault. You can swap #1 & #3 injector, if the misfire moves to #1 then you know the injector is bad/dirty. Description: How does a P0300 code trigger the check engine light? This code will trigger the check engine light as follows: The misfire detection monitor, a software strategy built into the computer, is designed to detect an engine misfire. Today I tried to spray brake cleaner on bent gasket as best I could with plenum on and it didn't change the idle. Possible Causes:. 4,5,6 front to back. P0304 is a cylinder specific misfire code, which means that Cylinder 4 is misfiring and causing the code. Theoretically there are two things required for combustion: Spark and Air/Fuel mixture. I took out the #3 cylinder spark plug and it looked like it had been hit with something. 0L Rubicon engine would not idle on a hot restart. Lack of power upon acceleration. 1 liter engine. So it may throw a cylinder 3 misfire, but when you start investigating you determine it isn't number 3 that actually has the misfire. She drove to work this morning and said it was hesitating and vibrating, yet no CE light. I have a 1997 Ford F-250 4x4 with a 4. The obd2 code showed a misfire in the #4 cylinder (P0304). It has brought up a code only two times. I have a problem with my bmw x5 e53 05 4. after I did that the light when off. Seeme it must be either coil of fuel injector, I would rather know the most likley culprit to change first. Spark plugs have a few thousand miles on them. Drive the vehicle several times with the conditions, such as engine rpm and engine load, shown in MISFIRE RPM and MISFIRE LOAD in the Data List. Found and rebuilt another used 4. Usually goes away after about a minute and then runs like a top. misfire P0306 - Cylinder 6 I have a 2004 4runner v6. MAF live data looks good, (g/s reading matches spec). P0303 Cylinder #3 Misfire. Found #3 & #5 cylinders to have misfires. ODB showed #4 Cylinder Misfire. This could cost $300-$400 for a 4-cylinder engine or $450-$700 for a V6. 2 Ohms - 1&3 terminals 1. I scanned it with VCDS and this is what i got. In his case, to repair the issue, he said he could either switch the whole coil pack or simply buy and replace the wire boots. If it is the #4 injector, how do I replace it. The problem could also be an injector, incorrect fuel mixture will also generate a misfire. There's been cases where the igniter would cause misfires at higher rpm. The mechanic said my engine probably would hav to be replaced or fixed. I checked the connector on the injector its getting power but not as much as the other cylinders. Replacing the coil in this case wouldn't resolve the misfires. :-\ To keep things simple and too ultimately figure out the problem, I am only doing one repair at a time. Before giving Autologic a call for help, the vehicle was in fact running lean, confirmed by fuel trim. I opted to do this at home so I picked up a coil and plugs and planned to replace over the weekend. Ever since the engine has been idling and running rough and I have been getting a P0303 code for a misfire on cylinder #3. A misfire occurs when an insufficient amount of fuel is burning in a cylinder. 0 v6 and I have a po302 code and it says misfire cylinder 2 when its actually cylinder 6 I have changed the plugs wires and firing order is correct I also tried a different coil pack same results but when I first driving Tue truck for the day it runs fine but after a bot it starts misfiring and I also get po174 lean. When I started it once a bunch of black smoke billowed out of the exhaust pipe. 7 v6 engine. I have a 2014. Today I tried to spray brake cleaner on bent gasket as best I could with plenum on and it didn't change the idle. 6L left cylinder heads on 2011-2012 vehicles and select 2013 vehicles. Here we have a P0301 cylinder misfire code on a Chevy 3. I checked No. Opened the hood today once I got home only to find the wiring harness to cylinder #4 chewed through. 4 while I was swapping out 3 since, unlike 3, it was the easiest to get to. Happened as I was rolling up to a stop sign not even accelerating. p0304 cylinder 4 misfire detected I have a 2005 grand cherokee laredo that has a 3. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 3. I pulled the plug and tested it with the plug wire on a. I ignored it and the check-engine light went off and has been gone since. i cleaned the injectors but still the problem is there. Also, yes, should have put new seals on the used injectors. The P0304 Audi code means that the cylinder 4 is misfiring or is randomly misfiring. You would be better off finding out which cylinder(s) are misfiring, and then directing your efforts toward that specific cylinder(s). Another FYI for you, Ford commonly mistakes cylinders. Thanks Alex. As mentioned, a cylinder misfire can happen due to a few reasons, and to make things simple, we created a table to show you exactly what repairs may be required to fix the misfire condition. Or and I heard this also; flash the computer to turn the MDS off as well. The misfire is worse without the #3 injector plugged in, so I know the cylinder does. Should be in order from 1 to 4. I went ahead and cleared the codes to reset CEL. Coil pack on cylinder 3 the best place to start?? Thanks. switch #4 and #3 injectors. My Honda's check engine light and VSA light were on. Step 1 How to fix 2000-2007 Mazda Tribute cylinder misfire. The check engine light was on and flashing at times and the computer had a pending P0301 cylinder one misfire code. Hi, I have a ML320 2000 with 165K miles. Learn about this problem, why it occurs, and how to fix it. Hey guys I have just purchased a 1999 Ford Ranger 3. I have already replaced both plugs and wires. We had a cold front come through and I had to replace my water pump, heater core, and radiator. This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. P0303 Cylinder 3 misfire Grand Prix Car Forums. Cylinder #4 Misfire Detected. It is a loud dead misfire. New plugs, moved the coil packs to another cylinder. That said with a misfire a good place to start is with a power balance test as shown in the video above. The loss of 25% of the engine's power output is the equivalent of a horse trying to run on three legs. After visiting a Mercedes Benz dealership, they told me I needed a new fuel pump, MAF, ignition coils and spark plugs with new wires!. Read the misfire counts of each cylinder (CYL #1 to #6) with the engine in an idling condition. the misfire could be the flywheel, BUT it could be a million other things too check the plug on that cyl, move that coil pack to a different cyl see if the misfire code comes back but that cyl, or it could be a burned valve, though not as common on 03s it still happens. 4,5,6 front to back. Having a a major dilema with a rough idle / Multiple Cylinder Misfire on my 2001 Chevy S10. If you are standing in front of the car looking at the engine: Cylinder 1 is bottom left, 2 bottom right, 3 middle left, 4 middle right, 5 top left, 6 top right. I recently brought my 01 V6 in to Strauss to get an oil change and 4 new brakes and rotors. Not sure where to go from here. Yep, that misfire is most likely from the fuel vaporizing inside the #3 injector caused by heat from the exhaust header collecting in that area. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 3. Hey everyone took the nitro in yesterday and got it back today. Misfire troubleshooting varies depending on the situation. Smell of unburned gas exiting the tail pipe. So it may throw a cylinder 3 misfire, but when you start investigating you determine it isn't number 3 that actually has the misfire. They all looked the same. The valve or valves stuck in high lift mode let in too much air and the cylinder runs lean and a misfire is the result. P0306 Cylinder #6 Misfire. In many instances, stalling ends up being an idle control motor at its limit or a failed motor. My truck started hesitating then finally threw a check engine light. The hotter the car, the higher/faster it will count. i ave an 06 LR3 but recently i scanned it and the message cylinder 2 and 3 misfire came up on the sysytem with the chevk engine lights on. The obd2 code showed a misfire in the #4 cylinder (P0304). I have a 2204 Jeep Wrangler TJ Sport 4. Cylinder 2 Misfire / P0302 on a 2007 JK So today I was out mall crawling with my 3 month old and on my way home and noticed a drop in RPM's and a severe shake in the. So then, the fault could lie in. Hey everyone took the nitro in yesterday and got it back today. Hello everyone, I just did the timing belt on my 05 IS300. Hey guys I have just purchased a 1999 Ford Ranger 3. There are a couple of odd things I have found through all of this. P0302 Cylinder #2 Misfire. Random Misfire, and cylinders 2,4,6 misfire. The engine idles a little rough and the cel is on. The valve or valves stuck in high lift mode let in too much air and the cylinder runs lean and a misfire is the result. Like the coil, it functions on pairs of cylinders, i. 7 liter tundra with 208,xxx miles. always # 4. 3L with 100K miles on it. What would cause number 3 cylinder not to burn like the rest of the cylinders could that cylinder be firing at the wrong time. The complaint was a bad misfire on cylinder #2 with some other random misses on the other cylinders. I will sometimes notice it running rough at an idle, but most times it seems to run fine. The diagnosis was cylinder 3 misfire, an apparent Honda problem and one that I've had fixed once before on this same car at the dealership where I bought the car. The problem could also be an injector, incorrect fuel mixture will also generate a misfire. I got a 2000 2. Type I 16 Check valve timing (Check for loose and jumping teeth of timing chain) (See page EM-22). I had it checke dthe other day and the codes showed an intermittent misfire on the #3 and 4 cylinders. 17) then the check engine light came on. Cylinder 3 and 4 Misfire I have had my outback for about a year now and have had struggles with cylinders misfiring for the entirety of that time. Light came on again (misfire on cylinder 4) - found out today that every valve on the right side of the engine is burnt. Exterior; Bumper, front chrome; Door handles, Black; Glass, solar absorbing, tinted; Grille, chrome surround; Headlamps, halogen projector-beam; Lamps, cargo area. 3 came up but there was also a code for multiple misfires. Replaced the #2 MDS solenoid, The wiring. Which is present. As you may already know, each cylinder needs 3 very specific things to produce power and they are: Air; Fuel; Spark; If any one of these components is missing, in any one engine cylinder, your 4. A car engine is very balanced from the factory and often with balance axles and different tricks to get as few vibrations from it as possible. • Misfire activity on cylinder #1Misfire activity on cylinder #1 and #5 has been corrected • Clid #3 l hCylinder #3 alone now shows consistent misfire activity on the Tech 2 scantool • Time to review fuel trim andTime to review fuel trim and vacuum readings again. Hello everyone, I just did the timing belt on my 05 IS300. Re: Cylinder #1 Misfire The front of the engine is the part furthest away from the transmission. Well they found a valve that was burned. This BMW Siemens MS43 DME (Digital Motor Electronics) MISFIRE repair service affects the M54 straight-6 cylinder engine commonly used in many 2000-2006 BMW vehicles. on the following monday took it to my trusted mechanic and he told me the following "A lot of the time when you have a lot of miles and it is specifically CYL#3 on a third gen, you have a cracked head". Start removing all the mark parts in red circles. A leaky valve cover gasket, for example, can flood the spark plug cylinders with oil intermittently, causing misfires. The code thrown was a #1 Cylinder Misfire. This morning, i went out and restarted the engine and the misfire seems to have gone away. I had the same problem with my car only cylinders 2 and 3. It is driveable and intermittent misfiring but I don't like to tempt fate here and not pushing it. does anyone have any ideas as to what the problem could be. Like the coil assembly, it's basically two separate circuits, one to trigger the cylinder 1&2 coil, and the other to trigger the cylinder 3&4 coil. P0302 Cylinder #2 Misfire. So then, the fault could lie in. Solution #4: Trouble Shooting A Misfire Code (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308) (YouTube #4). Misfire troubleshooting varies depending on the situation. A good friend phoned me from King of the Hammers last year, sharing that his late (2004) TJ Wrangler 4. We don't know the cause of the misfire at this point, but we know cylinder 3 needs to be checked. I have a 2005 Jeep Liberty with the 3. Check Engine Light. after I did that the light when off. i still have a misfire code for cylinder 3. P0300 Random, multi misfire detected. Had alot of codes on it, but after replacing a few parts, im down to 1 code: P0304 - Cylinder 4 Misfire Detected I can hear the cylinder alternating between misfiring and firing in the exhaust at idle. Anyhow my car started missing pretty bad out of nowhere. I have changed the spark plugs i have changed coil pack on the number 6 cylinder. Guess what, once again the engine light starts flasing and the shuddering begins again, as well as the TPMS light going off and on sporadically. I've got a 99 gmc sierra with the 5. At idle and with throttle. Car is misfiring. to recap, about a month ago, I had a 1,2,3,4 misfire. We would get the MIL and the code was P0303 - Misfire detected Cylinder #3. Also P301,P303,P305 Cylinder 1,3,5 misfire. Looked to be in. 4 mile journey, the computer saw 10 misfires in cylinder #1. The obd2 code showed a misfire in the #4 cylinder (P0304 I think). P0300 Random, multi misfire detected. None in #2, 1 misfire in #3, none in #4 or #5, 1 in #6. Now it just threw a 3 & 4 misfireso I'm thinking that since both went off, that narrows down what it could be big time. The car would barely run so I replaced the plugs with oem ngks. CEL misfire cylinder 4. P0305 Cylinder #5 Misfire. The loss of 25% of the engine's power output is the equivalent of a horse trying to run on three legs. PO 304 Cylinder 4 Misfire Was going to replace the sparkplug, but which is cylinder 4?! And any other suggestions for this CEL? update: bought new Iridium sparkplugs (same as old ones). 2 Faults Found: 6352 - Cylinder 3 P0303 00 [237] - Misfire Detected MIL ON - Confirmed - Tested Since Memory Clear Freeze Frame: Fault Stat. ending still runs a little rough. Note: Be aware that the #1 cylinder misfire code is a catch all. P0303 Cylinder 3 - misfire detected- Possible causes; Engine mechanical fault, wiring, ignition/fuel system, injector, ECT/MAF sensor, ECM. The code P0302 means cylinder 2 misfires, P0303 is the cylinder 3 and so on. The engine is a raw1 about 6months old with new spark plugs timing belt, tensioner etc. P0300 Mulitiple Misfire, P0303 Cylinder 3 Misfire, P0304 Cylinder 4 Misfire. I had all 6 sparkplugs replaced and the car ran fine for 3 weeks. by now the car is running fine, but I unhooked the battery to get rid of the CEL, a day or two later the light is back on. Speedtech 6266, stage 3 lpfp, index 12 injectors, ngk 95770 0. Drove it for a few days and it would misfire at idle but accelerate with out hesitation then for a few days it cleared out, well I moved and didnt drive the car for about another 4 months, then when I came to move it I tried to turn it on and the motor would turn over start for about 2 seconds and die. Any competent mechanic who does too little will have a scan tool (not just a code reader) that will give you real time data and misfire counters for each cylinder. I have already replaced both plugs and wires. Read the misfire counts of each cylinder (CYL #1 to #6) with the engine in an idling condition.