Ok engine is missing very bad through out the rpm range. Checked it out last night and heres what I found. I checked all the plug wires in the dark and found that all 8 is arcing. They arc right were the plug wires snap onto the plug. Is this normal? I have ngk tr55 plugs and took the #1 and #3 plugs out. Both are brown sort of like the color of rust. Also the (caps?) were loose and I screwed them back in. Also the coil was arcing too. I put the oringinal coil back on and that helped the missing on the lower rpm but still cuts out in high rpm range. So I took the coil back I bought almost a year ago and got a new one, ac delco btw. I bought a brand new gm opti in May of this year so hopefully its not that. Also have a new ICM. Also could a bad ground that goes to the coil cause it to miss. One other thing that helped it was I changed the coil wire with one I had laying around. Plugs and wires were purchased as same time as opti and installed at same time to. What do you all think is the problem or can you give me something else to check out. Sorry I wrote so much but this is very frustrating please help.

 

if all 8 are arcing in the dark that is no normal. IF and i say if it was me i would change the wires. I notice a lot of bad things happen to people with MSD wires. Just my 2 pennies. You may also check all your engine grounds namely the one at the coil as they seem to break or get screwed up when changing coils and whatnot.

 

I second the plug wire replacement, my Formula had a miss at about 2500 RPM and over for the last few days. Even though my wires were realitivly new (1 1/2-2 years old) I changed the plug wires this evening anyway and that cured the miss problem. BTW I went with the Stock AC delco plug wires.

 

oops, guess I need to change my sig, I have moroso wires on it now. My jethot longtubes finally come in yesterday so I guess when I install them will be a perfect time to install new wires. Another question does the color of the spark plugs sound right, there a rusty brown color? The ac delcos I took out were greyish color.

 

Oh yeah there is no SES lights coming on. So hopefully that rules out opti. How about ICM or coil will they make SES come on?

 

Sounds like your plugs are ok, my plugs were a rusty brown color also when i replaced them a few moths ago and my Formula ran fine at the time. As long as there isn't any carbon build up, physical damage or caked on oil they should be ok.