Its making me mad about this been to the track this years and the car is only going 106-108 mph and breaking up and studdering from 5400 plus. I have replaced coil,plugs,coil wire,fuel pump what else is there, the opti was done about 3-4 years ago 20k miles ago that is the only thing left to do. Any ideas from you guys or input would be great

 

Could be a million differnt things. Can u get a log of a run to find out whats going on in there.

 

injectors ?

 

Try the ignition controll module, it's about $70, but it could be your problem. Try the throttle position sensor first though, it's only about $30. Good luck!

 

I had a similar problem. My car would start acting like yours in high rpms - It turned out to be a bad o2 sensor. Not sure if that's the problem or not but that's what caused mine to act up. Are you getting good gas mileage?

 

If I knew nothing other than the car breaking up at high RPM's, I'd say that the order of likelihood would be: #1: Opti, #2: Opti, #3: Opti. Just my opinion though.

 

, what was causing my high rpm breakup, not to blame all bad things in life on the poor opti but it fixed my problem, 02 sensors were the next to go that helped on the overall stumble issue I shortly ran into after opti replacement.

 

bad fuel filter???

 

What is your battery voltage in the high RPM? If its low, it'll cause a miss.

 

i had a very similar problem with my 383 when i installed it, ended up getting an MSD 6AL box and it went away. Might be something to try