first post guys so here goes. the problem is my car misses at around 3000 rpm. it doesnt do it all the time. the CEL came on and its throwing code P0353. i changed both coil packs and all 8 plugs. still same thing. the light used to shut off after a few days now it just stays on. i do have some goodies on the car and they are. Vortech supercharger, methanol/water injection, upgraded fuel rails and injectors(39#) 8.5 mm plug wires(they look fairly new) and a few other mods but i dont think they pertain to the question. the plugs i put in are Autolite APP764 double platinum. they are gapped at .054". the only thing else i can think of to do is change fuel filter( although it looks brand new), change plug wires, and clean air filter( probably needs it anyway). any ideas? thanks for the help.

 

Your using Those kinda plugs gapped at .054" and their platinum.....uuugghhh change them. Get some NGK TR-6's and gap them at .030" You'll have to change them every 10kmi or so, but theit cheap and are the best plugs out there. You don't want platinum or a stock heat range and more so you don't want that big of a gap on a s/c'ed car. I say it's your wires to blame for the miss, but it's a tough call. One of your plugs could be shot? Worn down electrode? Chang'em anyways to NGK's.

 

i have the same problem and i found the problem to find so maybe its the same for u.

check your plugs and if they have oil on them u need to changed ur valve seals. whats happening is the oil is covering the spark plug which is preventing the spark from happening which is leading to the misfiring. thats what happened to my car. when i took out the spark plug and cleaned them it ran perfect but after a while (enough time for them to get covered in oil again) the problem happened again. when i checked the plugs they were again covered in oil. soooo u might wanna check that. if so just changed ur valve seals and clean the plugs and that should take care of it. as far as the actual plugs u might wanna get colder plugs if ur supercharged. ngk deffinately the best.

 

update. i think i got it solved. i did replace plugs wires and plugs to the tr6 gapped at .030and i reset the computer and the CEL went off. then this morning on the way to work it was missing baaaaad so i looked under the hood again and was messing with the harness connector that plugs into the driver side ignion coil and the tabs on the side that lock it in place were kinda messed up and it was forcing the connector to push itself back a litttle. so i squeezed it tightly on there with a couple tie-wraps and it drove like a brand new car the rest of the day so i hope that took care of it. thanks for the help guys.