My car flattens out at the top of 3rd and only in 3rd for a moment around 4500 RPM's, then it will pick back up. I'm CLUELESS as to what can be causing it. I thought that maybe it was my EGR, since I had gotten a code for it a couple of times. So I removed the EGR. I have also replaced my o2's and swaped the Knock Module for an LT4 module. This weekend I found a vacuum leak from the EVAP solenoid to the TB and fixed that. But the problem still remains. What in the hell could it be? I have no other ideas.

 

My guess would be opti, if the computer stops getting a cam sensor signal it cuts spark advance.

 

Except that OBD1s dont have a cam sensor.

At any rate, could be an opti problem, or a coil problem. Definetly ignition related, it sounds.

 

Hopefully it's not either of those. I replaced both of them last summer.