Mulitiple Misfire ?s, done a search

[1997redchevycamarors]

About a month ago i noticed that my car, when it was cold, would feel like it was misfiring but when it warmed up it was fine. The other day it started sounding like a machine gun when i accelerated and now it sounds like that all the time even at idle. I am not driving the car it is parked until i get it fixed. I have changed plugs, wires, and coils and it has seemed to get worse. Anything else to check? I have heard a vacuum leak could do it, How do you search for a vacuum leak? Any help would be appreciated. Thanks

[BLLDOGG]

Re: Mulitiple Misfire ?s, done a search

hmmm...maybe injectors

[astroglyph]

Re: Mulitiple Misfire ?s, done a search

ive done alot of research for my car on this, and if youre absolutely, positively sure its not a burned spark plug wire touching your exhaust, (quadruple check that), the next place to look would be plug wires arcing off of each other on your coil packs, check the ICM (the ignition control module, its the part that basically replaces the distributor in our distributorless cars, the coil packs sit on top of it and plug into it) you can take it somewhere to get it checked, or you could pick one up from autozone or whereever, swap it onto your car carefully so that you can take it back and get your money back if that wasnt the problem. Our cars can leak water off of the cowl, right onto the ICM, and thats why theyre known to go bad. A more likely culprit could be your o2 sensors, how many miles are on your car? Another could be your catalytic converter, if thats clogged up it could cause a problem..and the last one that would be something worth looking at are your fuel injectors being clogged. Could you give us some more info, like mileage, SES light/codes, last time your fuel filter was changed? Good luck

[1997redchevycamarors]

Re: Mulitiple Misfire ?s, done a search

I have right at 95000 miles on my car, the code it threw was p0300 and said it had mulitiple misfires. As far as i know the fuel filter has never been changed since I have had it and I have had it since 39000 miles. The guy at autozone had a list of 4 most likely causes. 1.plugs, wires, and coils. 2.vacuum leak. 3.injector fault. 4.fuel pressure too high/too low. I geuss i will try the icm. If it is the injectors, any recommendations on replace brand or size? I have heard that to search for a vacuum leak just spray the hoses with wd40 and if the rpms rise then you found the leak. Anyone know if this is a good way? And another question would it be wise to buy a spark plug tester to see if I am getting spark before I replace my ICM?

[1997redchevycamarors]

Re: Mulitiple Misfire ?s, done a search

UPDATE.

Today I unpluged and reseated all wires, made sure all plugs were tight and now it isnt misfiring as bad. Went to Autozone to get the code ran and it is P0304 cylinder number 4 misfire. But on the way home the SES light went out but i can still feel a misfire. What can this mean? I have done searches and alot of people say it's the ICM without certainty. Some say get the injectors cleaned. A few people say they can never get it to stop misfiring. Am I in for a long haul?

[Shodown]

Re: Mulitiple Misfire ?s, done a search

My car is doing the exact same thing. It will misfire like crazy, I change the plugs, it goes away and 1500 miles later, its back! After changing the plugs, the old plugs dont look all that bad.

New plugs = no misfire. 1500 miles later = misfire again. ???

I have changed the plug wires too. My car has 67,xxx on it. Its not my cat cuz I just got a new one installed and it was having this problem before that. BTW, its not throwing any codes either.

[1997redchevycamarors]

Re: Mulitiple Misfire ?s, done a search

My car is doing the exact same thing. It will misfire like crazy, I change the plugs, it goes away and 1500 miles later, its back! After changing the plugs, the old plugs dont look all that bad.

New plugs = no misfire. 1500 miles later = misfire again. ???

I have changed the plug wires too. My car has 67,xxx on it. Its not my cat cuz I just got a new one installed and it was having this problem before that. BTW, its not throwing any codes either.

Have you tried having your injectors cleaned or changing your ICM?

[Shodown]

Re: Mulitiple Misfire ?s, done a search

Not yet. After reading this thread I will though.

[ploppel]

Re: Mulitiple Misfire ?s, done a search

I had (hopefully it's fixed now) the same problem. Replacing the ignition mudule ($157 at AdvancedAuto) seems to have fixed the problem... I just installed it last night so I'll wait a few days and see how it runs.. :bowdown:

[1997redchevycamarors]

Re: Mulitiple Misfire ?s, done a search

I was told that it wouldn't be the ICM if there was just one cylinder misfiring. And that it would more than likely be a dirty injector or it could be that I am using the bosch platinum +4 plugs. Is anyone using the platinum +4's? He told me that I should go and buy some AC Delco to put in it. Would that be a good thing to do? Or could the plugs be the cause? I don't have 15 miles on them.

[98DC]

Re: Mulitiple Misfire ?s, done a search

Mine was doing the same thing.
1. Replaced the plugs and wires. No help
2. Took it to a shop who replaced the first two coil packs and one of the wires. Worked but I could still feal it missing
3. I replaced the last coil pack. all good for about 4 minutes then it came back mad as H#LL
4. As a last ditch effort I replced the ICM. Didn't help what so ever.
5. Giving up I took it to the dealership, The heat shelds were missing from all cylinders and the wires were melted to the block.

I got it back it it's running like a pro again.

Although I can not prove this, I think that it was the ICM the whole time and that the first place that I took it to removed the heat shelds and forgot to put them back on allowing the wires to melt.

[1997redchevycamarors]

Re: Mulitiple Misfire ?s, done a search

UPDATE

I replaced the Bosch Platinum +4 with AC Delco Iridium plugs and that helped tremendously with the miss. It's in the shop now getting injectors cleaned. I will upgrade when I get it back. If that doesn't get rid of the miss completely i guess I will change the ICM.