Starting in early May, my car developed a misfire. About 2 years before, it had done the same thing and turned out to be the optispark. Thinking it was the same thing, I bought a new opti (DynaSpark) and a cam package...

*Side note* It first started misfiring in April after I ran through a deep puddle. It only missed for about 10 minutes after that and then cleared up. I figured I had just got something wet and it was over. A few weeks later, I did the same thing... freaking rain. Once again it cleared up. Then finally in May, without running into water, it just started misfiring again one day...

The following parts have been put on my car:

GM HotCam Kit
Hardened Pushrods
March Underdrive Pulleys
DynaSpark distributor
New MadZ28 tune

After all that, it still has a misfire that sometimes starts when cold, sometimes takes a little time to warm up. I had it scanned at the shop and it seemed to be pretty random, with some cylinders being worse offenders than others.

I just bought plugs and wires which are going in tomorrow. If that doesn't fix it, what else is left? Ignition Control Module (ICM) and Ignition Coil? Is there anything else it could possibly be?!

*Another side note* I was having trouble reading my old tune from my OBDI PCM and had to send it in to get it reprogrammed. I narrowed it down to an issue with the car and didn't want to take a chance uploading the new tune and messing up the PCM. However, the car also has the misfire with the OBDII (stock) PCM, so that seems to rule out the PCM...

Thoughts, anyone?

 

Opti, ICM, and Coil. One of those is your problem.

 

Kinda what I figured. ICM and coil aren't that expensive from what I remember. We'll see what happens...

 

my mist like that and it waas the opti

 

Did plugs/wires and re-did the lifters while the engine was warm. Seemed to cure it.