I've got another high rpm missfire. I replaced plugs (NGK tr 55's) and my wires two to three months ago. In first gear I dont really notice it but once I hit second and it hits five grand it starts missing really bad. I'm pretty sure opti spark you normally have a miss fire through the entire rpm range. So what else should I look at? Only thing I can think of is when my car overheated that it could have messed up my plugs?

 

I think your fuel filter is clogged. Cars with clogged fuel filters often run ok at lower rpms but start missing at higher rpms. Fuel filters are cheap.

 

I had the same problem - it turned out my o2 sensors were bad beleive it or not. After 3k or so it would miss really bad. You might want to check that out - Mike

 

If your o2 sensor was going bad, wouldn't you get a code for it?

 

O2s aren't used at wide open throttle.

 

If this is indeed true, perhaps that is why during WOT, my SES light turns off. then it turns back on after I am done in WOT. But then why am I not getting a code for an o2 sensor? Maybe I need to hook up a scanner to the car and check out the millivolts.

 

I'm not saying that is the problem. It's just that I had the same problem with my car. It would only start to miss at high rpms - low rpms was fine. My gas mileage was really really bad. - Mike

 

I was having a hesitation/miss? problem at low RPMs, and I just had my O2's replaced today and the car drives a million times better.....just like new.

FYI......

 

My car used to run fine in the low rpm range then anything above 5 grand it would miss. I tried changing plugs and wires, still missed. Finally I ended up changing the opti now it runs like a champ.