Random Multiple Cylinder Misfire

[camaro_guy]

Everytime I run for a while WOT in second or third gear the SES light comes on and everytime I run the codes it spits out Random Multiple Cylinder Misfire. Does anyone know what might be causing this?

[9t9fb]

I just got done fixing this problem on mine.
This could be a few things, so start with the cheep and easy things.

1. When was the last time you replaced your spark plugs? This could be on of those things.
2. Have you replaced your plug wires? Or check to see if they are arching.(look for burn marks on them or look at them with the engine running in the dark, you can see the sparks is the're arching)
3.Then are the coils. One of them may not be passing spark to a cylinder.
4. And last the ignition module could not be probiding electricity to one of the coils.

[Shirl]

Yep, what he said ^^^ Plugs and wires are always the first things to check with a misfire.

[Yaba3800]

mine did the same thing when i was racing. i have an msd waiting though ;)

[EvilSmirk]

Re: Random Multiple Cylinder Misfire

I've been getting the same message lately. I've replaced the plugs, wires and coils. What else should I try?

[97rs4life]

Re: Random Multiple Cylinder Misfire

I've been getting the same message lately. I've replaced the plugs, wires and coils. What else should I try?

#4 on that list that was posted a few posts up

[EvilSmirk]

Re: Random Multiple Cylinder Misfire

If the ignition module was going, wouldn't it prevent all of the cylinders from firing?

[Silver 99 Camaro]

Re: Random Multiple Cylinder Misfire

Autozone will check the module for free to see if it works. They cannot, however, check individual coils. If you've already done plugs, wires, coils, and the module checks out fine, then you probably have a fuel issue like bad injectors or something of that nature. If that's the case, you need to get it hooked up to diagnostic software to tell you which cylinders are misfiring so you can check everything on those particular ones. If ALL the cylinders are misfiring, then you might have a fuel pressure issue such as a clogged fuel filter, failing fuel pump, or bad fuel regulator.

[EvilSmirk]

Re: Random Multiple Cylinder Misfire

Thanks for the reply. The next thing I'll do is take my ignition control module and see what's up. If that checks out fine, I'll start looking at fuel delivery being the problem. Based on what you said, taking it to a shop and having them run a diagnostic machine capable of giving more than just a general code seems to be in order. Am I correct?

I really don't want it to be a valve or cylinder related issue and certainly hope that it is not. The air filter looks fine, if the ignition control module checks out okay, then it seems to me that the fuel system definitely needs to be looked over.

I'll let you guys know how it goes.

[1999Spectre]

Re: Random Multiple Cylinder Misfire

yes they can check your coilpacks, i did it all the time when i worked there. disconnect your wires and take the whole thing up there. they will check the primary and secondary on the coilpacks. try changing your fuel filter too, that can also cause that problem.....

[EvilSmirk]

Re: Random Multiple Cylinder Misfire

The coil packs should be good since I just put them in on Tuesday. It's the ignition control module that I'm worried about now. Can I just bring that in, or are they going to want to have the ignition coils with it as well? I'll pick up a fuel filter while I'm there as well. Chances are, even if the filter wasn't the problem, it's probably not great now.

This is going to be a newbie question, but how do I locate my fuel filter and how do I replace it?

[EvilSmirk]

Re: Random Multiple Cylinder Misfire

It's been really busy these past few months with trying to get the ADS hardware sent out to the JSF A1 aircraft.

I'm going to take the ICM into Advance on Friday, but still had the previous question regarding the fuel filter. If the ICM is the problem, what would I expect them to say? Electrical shorts, arcing, etc.

[slow6]

Re: Random Multiple Cylinder Misfire

fuel filter is right next to driver's side wheel. infront of LCA

[EvilSmirk]

Re: Random Multiple Cylinder Misfire

Swapped out the ICM, which fixed the problem. Yeah.

Also changed the fuel filter and added an STP fuel system cleaner when I filled up this morning.

Things seem to be running great.

[av6xperience]

Re: Random Multiple Cylinder Misfire

great to hear things are better. stp wont do anything from what i hear, pour a can of seafoam into the gas tank