I need some help running down a problem. My 1991 1LE Trans Am 305 TPI misses or cuts out at high revs. Runs great as long as I keep it under 3k, but for track days, when I run it above 3.5k, it either misses and won't rev above 4.8k or cuts out and just bogs at 3k. Things I've fixed or looked at:

-new plugs, wires, cap, rotor, coil, pick-up, dist module
-had a guy flash the chip to look at the chart and tweak it
-new fuel filter and pressure check at the rail

I'm stumped. I have a track day coming up next week and it's the first step towards getting my comp license so I really want to run this down....any help appreciated!

KO

 

To be honest, it sounds like a fuel pump problem.

 

Fuel pressure at the rail may be good when you check it but under load is a whole different story. Tape the gauge to the windshield or do whatever you gotta do, you have to see fuel pressure at the very moment the problem is occurring.

 

Check your catalytic converters. I had a similar problem with my car, which is very similar to yours. I looked over all of the things that you mentioned. It turned out to be clogged catalytic converters. My car now runs like a raped ape.

 

I've been going back and forth between ignition and fuel. I'll try to get a gage set up so I can read fuel pressure at speed. Also, a mechanic here told me they sometimes actually slit open the pipe ahead of the cat-conv to see if it runs and if the cat is plugged. If it makes no difference, he just welds up the slit....saves the cost of replacing. I do have a replacement fuel pump but have been hoping that's not it!! Arrgggg! I don't mind things that just break. I hate things that just go bump in the night.

KO