P0302: misfire cylinder 2 (1996 GT)

[JC316]

If the light isn't coming on, it's likely just a pending code that hasn't fired off yet. I never understood how the PCM knows it's a misfire with no knock sensor, much less how it knows which cylinder.

This is a stupid question, but it has happened to me. Are you for sure that you have the spark plug wires hooked up correctly? They go every which way and it gets confusing. If someone screwed up and you are just going wire for wire, then you might have some wires in the wrong place.

Have you confirmed that the wire is actually sparking and the injector is clicking? If so, you need to do the compression test.

[CWO]

If the light isn't coming on, it's likely just a pending code that hasn't fired off yet. I never understood how the PCM knows it's a misfire with no knock sensor, much less how it knows which cylinder.

This is a stupid question, but it has happened to me. Are you for sure that you have the spark plug wires hooked up correctly? They go every which way and it gets confusing. If someone screwed up and you are just going wire for wire, then you might have some wires in the wrong place.

Have you confirmed that the wire is actually sparking and the injector is clicking? If so, you need to do the compression test.

Oh, I'm sure. I've checked it at least a dozen times. Driver side coil pack, second cylinder on the passenger side. I've pulled the plug from both sides while the car is running and get spark. I can't say that I confirmed that the injector is clicking though. Im not really sure how to do that. I'll look into it.

[CWO]

Isn't that just to bleed off pressure?

Yes, but I was addressing the comment of running out of gas.

[JC316]

Oh, I'm sure. I've checked it at least a dozen times. Driver side coil pack, second cylinder on the passenger side. I've pulled the plug from both sides while the car is running and get spark. I can't say that I confirmed that the injector is clicking though. Im not really sure how to do that. I'll look into it.

Just start the car and use a screw driver as a stethoscope. If you hear it clicking, you know that it's got power and is opening.

[DON SVO]

If the light isn't coming on, it's likely just a pending code that hasn't fired off yet. I never understood how the PCM knows it's a misfire with no knock sensor, much less how it knows which cylinder.

The PCM checks the event time of the reluctor wheel on the crank trigger/cam sensor every cylinder firing. A misfire event will slow the RPM down on that firing, the PCM will store that event and throw a CEL with multiple duplication.

[shumpertdavid]

The PCM checks the event time of the reluctor wheel on the crank trigger/cam sensor every cylinder firing. A misfire event will slow the RPM down on that firing, the PCM will store that event and throw a CEL with multiple duplication.

yep, pretty well explains it, misfire technology has been a big help in making quicker more efficient repairs, expecially with the always failing random coil on plug coils with ford primarily and most every make at some point.

OP is this a dead miss, meaning it misses always at idle, part throttle, wide open. Or is it a miss more at idle that seems to disappear as rpm increases, or more a misfire under load like it cuts out under heavy throttle or climbing hills etc.

[JC316]

The PCM checks the event time of the reluctor wheel on the crank trigger/cam sensor every cylinder firing. A misfire event will slow the RPM down on that firing, the PCM will store that event and throw a CEL with multiple duplication.

Learn something new every day. Thanks for the explanation.

[CWO]

yep, pretty well explains it, misfire technology has been a big help in making quicker more efficient repairs, expecially with the always failing random coil on plug coils with ford primarily and most every make at some point.

OP is this a dead miss, meaning it misses always at idle, part throttle, wide open. Or is it a miss more at idle that seems to disappear as rpm increases, or more a misfire under load like it cuts out under heavy throttle or climbing hills etc.

Well, it's barely noticeable at all really. The only time I can really tell anything is wrong is WOT, it doesn't sound quite right and seems to vibrate more than I think it should, and of course it hesitates of course.

[shumpertdavid]

ok, usually compression type misses are more noticable at lower rpms and will be "masked" more as rpm goes up. If yours is more under heavy load and with what all you've change, you've about covered all your options. A compression test wouldn't be a bad idea just to cover basics, same with leak down test but that requires a tool most people don't normally own, local parts house will likely have one to rent/borrow.

One thing you can try and it's pretty easy and good maintenance would be to clean the airflow meter. You can buy mass sensor cleaner at the parts house, DO NOT USE CARB CLEANER OR ANY SOLVENT BASED CLEANERS. Remove the meter from the mass housing (for best cleaning results, it can be done with everthing assembled but hard to get all of sensing diodes cleaned) and spray the 2 little diode looking pieces. If it looks like they have little hair or fuzz balls then cleaning this may clear your running problem

[JC316]

ok, usually compression type misses are more noticable at lower rpms and will be "masked" more as rpm goes up. If yours is more under heavy load and with what all you've change, you've about covered all your options. A compression test wouldn't be a bad idea just to cover basics, same with leak down test but that requires a tool most people don't normally own, local parts house will likely have one to rent/borrow.

One thing you can try and it's pretty easy and good maintenance would be to clean the airflow meter. You can buy mass sensor cleaner at the parts house, DO NOT USE CARB CLEANER OR ANY SOLVENT BASED CLEANERS. Remove the meter from the mass housing (for best cleaning results, it can be done with everthing assembled but hard to get all of sensing diodes cleaned) and spray the 2 little diode looking pieces. If it looks like they have little hair or fuzz balls then cleaning this may clear your running problem

+1 on the MAF, but be VERY careful when spraying it. I won't even use full pressure with the spray because they are so fragile.

[shumpertdavid]

I doubt the maf will be the result of misfire code, I forgot about that part

[Reefer Rae]

Maf will cause cause a lot of codes including p0300 but not a cyl specific misfire code .

[CWO]

...and now my radiator is steaming. Not leaking, or dripping.... steaming, until the fan kicks on anyway. The temp gauge never moves over halfway. WTF

[CWO]

Awesome.

So I did the heater core today, it works great. Not sure why, but I decided to check the oil. I did it several times and every time the dipstick was completely dry. I changed the oil a few weeks ago as a precaution. Went to Wal-mart to pick up some more oil (not really understanding why it's dry). Unscrew the oil cap and the inside of the oil cap is all milk-shakey.

So, now I guess I know why I have a cylinder misfire and the radiator is steaming.

This car is such a piece of shit.



So changing a head gasket soon.

[DON SVO]

Awesome.

So I did the heater core today, it works great. Not sure why, but I decided to check the oil. I did it several times and every time the dipstick was completely dry. I changed the oil a few weeks ago as a precaution. Went to Wal-mart to pick up some more oil (not really understanding why it's dry). Unscrew the oil cap and the inside of the oil cap is all milk-shakey.

So, now I guess I know why I have a cylinder misfire and the radiator is steaming.

This car is such a piece of shit.



So changing a head gasket soon.

I'd do the PI head swap. You're already in there.