I have an 87 iroc with the fast burn 385 with the 430 kit witch is 430 hp and 430 ftlb of tourqe. I have hooker 1 3/4 super comp headers with the mufflex 4 inch exaust system, tpis mini ram and accell 24 lb injectores with a custom burned chip form tpis. i also have the accell fuel pump that put out 34 gph. My questoin is when i hold the rpm's at 2500 or 3500 or whatever it pops out the exhaust like it is missing but at wot it runs just fine and dont miss a bit.

 

Mine did that right before the ignition coil died.

 

Also when i get to the end of the track and let off of the gas the car does one big loud backfire, but it has an exhaust leek at the collector.

 

If you have an exhaust leak at the collector you could be getting some fresh air to your O2 sensor. This can screw with your computer.

If that's not the problem I would have to guess that the chip from TPIS just isn't as perfect as you might think. My best suggestion would be to take a look at the PROM board and see if it's for you. It looks like you've already got a ton of bucks in that motor, you might as well get the most out of it by burning your own custom chips.

But regardless I would say that the popping sound is a tuning issue, most likely related to the computer's program.

 

Might be a dead spot in the TPS.