This has been a problem with my car since I have owned it. Every now and then if you try to punch the throttle real quick, it'll just "POP!!" or back-fire. I have checked the TPS and it checks out fine. Also right around 4500 rpms it almost seems like it is banging the rev limiter. As far as I know there is no rev limiter installed via programming. Any good trouble shooting idea's?

 

I'm having pretty much the same problem. I've been on forums since I've owned the car, and soon found the Opti-spark is usually to blame with symptoms like this. I have yet to replace my Opti, but this should fix my problems (which are very similar to what your experiencing). This is not to say you couldn't have other ignition/sensor problems, but the distributor is usually a good place to start.

 

Can you datalog?

 

So far I haven't been ableto get Datamaster to connect correctly. I'm pretty computer savvy but can't seem to get it just right. I have gotten a new laptop so maybe that will be the ticket. Unless something is wrong with my comm port in the car. I put a new opti on the car when I bought it and the condition still existed after that. Needed a new one either way though. It now has at most 14k on it and I've had the car for 7 years.