Multiple misfires

[CamaroGeek]

Ok, i've searched for this and haven't found much. I am having a very bad misfire problem. I have read through many of the misfire threads, and havn't found a new direction. I've had misfire problems on and off for a while. Shop replaced cyl 1 plug about a month and a half ago cause of a misfire. Seemed to run very well. Then a few weeks later i had bad misfires. I finally found the time to go to autozone and have it scanned. Multiple misfire on 5 cylinders. So i bought plugs and wires (did them under 10k ago) hoping to remedy. One plug i took out by hand it was so loose. The others have a lot of carbon buildup on them. Could this be the ICM? I am leaning away from the coils cause they all started at about the same time. Also whats a good way to check which cylinders are and aren't misfiring without a scanner?

Thanks for your help.

[LwnGy83]

If you changed plugs and wires, and you're still miss firing, it's probably your coils. I had two go out at the same time. It just happens like that sometimes. If it's not your coils then it's your ICM... but I'd check your coils first b/c they are alot cheaper than a new ICM... If you haven't checked into a new ICM it's like $150 at Autozone. So, I'd start w/ your coils. Good luck man.

[montytrmpt]

I'm having a bad idling issue, sounds kind of similar. Unfortunately, my computer won't scan so i'm left in the dark. I'm leaning on coils and possibly a crankshaft sensor. That sensor apparently tells the ICM when to fire the coils.

[Den69RS96]

Sounds like your ignition control module is bad. I doubt all three coils went bad at the same time. Buy a spark plug tester (about$15). Its basically a spark plug with a clip attached to it. Attach a wire to the spark plug test and the clip to a ground. Have a buddy crank over the car. Check each cylinder. If a coil is not firing the two cylinders attached to that coil should both be out. Switch its location with one that works. If two more cylinders go out after you switched the coil locations, than your ICM is bad in addition to a bad coil. If only two are still not firing than its just the coil. Hope that makes sense.

[jbfirebird22]

i had the same issue before, turned out the issue was the ICM

[Die Ford V8]

montytrmpt i think your problem is EGR related and/or 02 sensor related. (before you buy an egr valve remember they are over $340 i worked the crap out of a 3.4 and it always had idling issues. your computer if it was able to be read is probably trying to tell you "map sensor high voltage/low pressure" or visa versa. check all vacuum lines

as for the first post, i am having the same problems. if you change your coils and it works or doesnt work either way, throw me an email


good luck

[Die Ford V8]

ICM?????

whats is stand for, i think i just flushed my brain in the toilet and cant remember

[RallyRed 98]

ignition control module.

it COULD have been all three coils at once, but it's not likely... when one goes out, the others aren't far behind just by virtue of the way the ignition works.

i would look toward the ICM on your car, camarogeek. i chased the same problem with new wires, plugs, and coils and anythign else i could think of before i checked the ICM. i've had two go out on me so i'm not too impressed with the system's durability.

[jbfirebird22]

another thing with the ICM is, it may not throw a code if it is not totally screwed.mine didnt throw a code for about 2 months after the problem started. you may not get the code for it till way down the road after you have had everything changed. if plugs,wires, coils doesnt fix it, its prolly the icm

[montytrmpt]

Good luck CamaroGeek, I agree with the rest of these guys, the ICM is the likely culprit. Fortunately, it isn't all that difficult to replace and If you wanted to risk it, you can pick up a cheap one on eBay.

Die Ford V8, thanks for the tip. I've replaced coil packs, IAC valve, and plugs. I'm pretty confident the problem isn't in the ignition. I think I have it down to that EGR valve and/or a cat problem.

[Die Ford V8]

do away with the cat, it frees up horsepower and is better for the environment since you get better gas mileage. (less burnt fuel is better in my opinion)

you dont have to worry about sensors and its only like 4 or 6 bolts. takes about 20+ minutes to bang the stuff out. bolt it back up, (make sure nothing is left inside)drive, and enjoy.

your exhaust will sound a bit more beefy too.

in my friends firebird we unpluged one of the o2 sensors and the engine liked the stored code better than the sensor reading.

I would try new 02 sensors ($20 or so) and knock out the cat. find a good used egr with a moving soleniod in that thing that plugs in the top of the solenoid. also check all vacuum in that area for leaks. try seafoam and then just watch your engine compartment like a hawk. video tape it and youll find where the first sings of smoke are.

dont use the whole thing of seafoam at once (1/2 to 2/3 at the most) and do a search if you want info about it.

again, good luck and happy troubleshooting ;)

[jbfirebird22]

the only prob with the new ICM is that it is a tad pricey bought new, if i remember right, mine was like 120 bucks or so, however, that is what the mech
said. who knows.

[Need4Camaro]

I did plugs, wires, used EGR, AIT Sensor, PCV Valve, and Fuel Filter all around the same time and I'm getting a light stumble when I drive... Accelleration and all is still smoothe but I still have this light stumble... Also can the ICM decrease gas milage?

[LwnGy83]

I'm having the same problem as Need4Camaro. Everything is working properly, says me, and my mechanic, but I still have this stumble. I'm thinking mine is from taking off the throttle body screen. I kind of thrashed when I was taking it off to clean the throttle body. and I'm thinking that could be the problem. Maybe that's what's goin on w/ you Need4Camaro.

[jbfirebird22]

Originally posted by Need4Camaro:
I did plugs, wires, used EGR, AIT Sensor, PCV Valve, and Fuel Filter all around the same time and I'm getting a light stumble when I drive... Accelleration and all is still smoothe but I still have this light stumble... Also can the ICM decrease gas milage?

if your stumbling its basically misfiring. so id imagine that it could decrease gas mielage