3.4 misfire help

[tomham]

my friend has a 3.4 1995 camaro it has a misfire that is horrible in low rpms especially under load it has between 100 and 120 psi of compression on all cylinders all the injectors are clicking when listening to them. it has new plugs and wires and spark to each cylinder the plugs are turning black already so it is running rich and the #4 cyinder is by far the worst it was wet when i pulled it #3 and #5 both look like they are running about right all the other ones are running rich


any ideas i am lost oh and the check engine light does not come on and my code reader says error when trying to pull codes

[tkoforpresident]

Re: 3.4 misfire help

could be your ignition control module or one of your coil packs.

[tomham]

Re: 3.4 misfire help

but i have spark on all the plugs so it shouldent be the icm or a coil pack should it?

[tkoforpresident]

Re: 3.4 misfire help

but i have spark on all the plugs so it shouldent be the icm or a coil pack should it?

not exactly. :slap:


your coil packs and icm work differently as your rpms change. while you might have good spark at idle, you might be missing as soon as you start to give it gas.

what would i do if i were you?

1. buy the icm off of me that is in used but good cond.

2. buy ONE new coil pack.

3. replace your icm with mine.

4. swap the new coil pack with each old one until your misfire goes away.

that would be the cheapest thing to do. the most expensive but certainly less aggravating would be to buy a brand new icm for like 60$ on ebay, and buy 3 new coil packs at 30$ a piece.

[tomham]

Re: 3.4 misfire help

yes but usually icm's or coil packs stop working at higher rpm's and the miss seems to go away then

[tomham]

Re: 3.4 misfire help

oh also i forgot to add that it pops when it misses

[jnxV6]

Re: 3.4 misfire help

I had a problem similar to yours where when I was accelerating it would stumble and miss, and when I was cruising along it seemed fine. The problem that I had was a coil pack went bad. When you get it to higher rpms is that while driving or is it when the car is in park?

[tkoforpresident]

Re: 3.4 misfire help

yes but usually icm's or coil packs stop working at higher rpm's and the miss seems to go away then

stop working?? what are you talking about?? your car still needs spark no matter what your rpms are....

[tomham]

Re: 3.4 misfire help

yes i dident mean stop working but if they are weak the fault shows up under higher rpms. and in higher rpm's its beter in both park and driving

[tomham]

Re: 3.4 misfire help

ok so an update new coil pack didnt do andything and a new o2 sensor dident really do anything either it pops bad when accelerating and is really bag around 2k rpms even does it at cruise then

any ideas please help!!!!

[tkoforpresident]

Re: 3.4 misfire help

Icm....

[tomham]

Re: 3.4 misfire help

i dont really want to replace the icm with out knowing that that is what is wrong. any other ideas or tips on how to test the icm to see if it is bad. i did put a spark tester on it and reved it up it appeared to not be missing any sparks

[tkoforpresident]

Re: 3.4 misfire help

i dont really want to replace the icm with out knowing that that is what is wrong. any other ideas or tips on how to test the icm to see if it is bad. i did put a spark tester on it and reved it up it appeared to not be missing any sparks

i told u ... u can buy my used one for like 20 dollars. to be more convenient you should have replaced the coil packs and the icm at the same time but oh well have it your way. did you try replacing all 3 coils with the new one? :poke:

[tomham]

Re: 3.4 misfire help

i told u ... u can buy my used one for like 20 dollars. to be more convenient you should have replaced the coil packs and the icm at the same time but oh well have it your way. did you try replacing all 3 coils with the new one? :poke:

yes i did try that and i dont wanna throw another $20 and wait a week it is not my car so im not going to have the guy just throw parts at it

[Opontee]

Re: 3.4 misfire help

Does the #1 plug look like the #4? Do 2,3,5 and 6 look the same? I just replace my 1-4 coil b/c of the same problem. With the car off, pull the plug wire, stick a phillips screw driver in the plug boot, start it and hold the screwdriver (but the handle) close to a ground. slowly pull it away from the ground. The spark should jump about an inch or more before it doesn't spark anymore. If it quits sparking at a 1/4 inch, you probalby have a bad coil. At least that's what happened to mine.