ZX636RIDER03

Iv'e got some serious issues with my ignitions system. im getting a obdII code of multiple missfiring. Ive checked all of my spark plugs and wires and they are in tact, i also changed out my ignition coil. The funny thing is that when i first start it up i dont have any problems but when i hold it at about 3000 rpms for a few minutes it starts to misfire. the engine has about 110000 miles on the accessories. If anyone has any suggestions let me know please.

sssalah

Check the optispark cap and rotor, it's a distributer and it need these replaced after this much usage, better yet replace the whole optispark unit.

Joe B

On a past Camaro , I had my optisparks rotor work it's way loose after only 60thousand miles.....anytime the motor was reved, the rotor was jittering around inside causing it to break up and misfire......and even if the opti is "not" your immediate problem (but sounds like it is if all else checks out).....Like sssalah mentioned, I would bet it's ready to go out on you real soon anyway with those miles on it...It seems "most" guys get between 75 to 90 thousand miles out of them...If you don't go for one of the expensive aftermarket units(MSD, DEL, Acell, Ect...)change it out with a whole new GM unit(not reconditioned)...make sure to seal every seam on the unit with beads of silicone RTV, remove and clean the two rotor screws, and then reinstall them with red highstrength loctite and it's ready to go..... you can get the one you need(vented) for $225 off ebay, from a GM parts dealer.....Iv'e purchased several from that source and have never had an issue......

ZX636RIDER03

you know whats weird i just changed out my egr valve and dumped a whole bunch of fuel system cleaner in my tank and now it runs great. i might of had a clogged injector or something. But i do agree the optispark does need to be replaced hopefully i can save some cash to get a new one if possible. thanks for the info sssalah and joe, appreciate it.