Quote Originally Posted by Spasm View Post
The normal solution to this problem is to check/replace: oil change,air filter,pcv valve,plugs,wires,distributor cap and rotor,bottle of injector cleaner,fuel filter,check fluids

Yea I have done almost everything on that list, actually every single thing except pcv valve, whats annoying is no one knows, they are all clueless. I am not using low quality fuel, I was told water in the fuel, or lower octane, I have been putting nothing but premo in it for the past few weeks. The only thing that makes less sense for it to be the computer is the fact that it will not do it until the engine warms up. I take that back it may still be doing it, but its no where near noticeable. It will not backfire unless I just jam the throttle down when its misfirng, then about 10 seconds later it will backfire. It does do it in other gears, but because the car is accelerating so much in 2nd I feel it alot more there, and when it starts misfiring, it will literally throw me forward in the seat, almost as if I had hit the breaks. -- thats on a bad day. Whatever it is, it is heat related. Once the engine warms up good, say at a few stoplights back to back, it will start doing it, every time. Again thanks for your help guys

Oh and the thread you linked, that guy is talking about reving the engine up sitting, my car will not do it unless it is under load. It revs just fine all the time, even if it just misfired, If i was to hit the clutch in and rev it, it would rev without a problem, its only under load and heat really.
Fuel is too rich combined with a high temperature causes pre detonation. Based off of what you said any of the following can fix your problem(or a combination):

  • Adjust cam timing or reprogram computer to the correct timings based off pre detonation.
  • Use lower quality fule to prevent pre detonation
  • Reduce the compression
  • Reduce the internal tempature

Actually if you use a fuel that is to high of quality it will simply not burn correctly and will cause shit to build up in the pistons. It can also cause the problem he is having. Using higher quality fuel will improve MPG and HP but you need to reprogram the engine computer to use it.

If you use a fuel of too low quality you can have start problems and will lose performance. For example my boat on premium will have problems starting from cold. If I put 110 octane mixed with 92 at 50/50 it will work correctly.