I have a 1988 Camaro with TBI and auto Trans. I replaced the engine and trans with a new engine and trans for a 1988 Camaro. This was done due to very high milage. Cat was also replaced due to high back pressure. Engine starts fine and idles perfect. Timing is spot on and no vacum leaks. Engine pulls good until floored. Once floored engine light comes on and engine idle and performance is very ruff. Acts as if the ignition timing has change as the engine temperature will start to increase. Once the car is shut off and restarted everything returns to normal. No codes are in the memory for the computor. Help!

 

if you have ses light you should have codes. i'd look in ot that a little more. check the data stream while it's running for codes or out of parameter operation

 

Just a crazy guess, but it sounds like it may be getting lean when you go to WOT, since you are getting some overheating at the same time. You'll also get a little backfire sometimes when it's lean. That could be from low fuel pressure on EFI systems, and possibly a restricted fuel filter.

Is it possible that the EGR is opening due to an incorrectly connected vacuum line at the solenoid? You could temporarily disconnect and cap the EGR for diagnosis.

Also, you mentioned "no code", but did you at least get a "12"? If you have missing distributor pulses, the "12" will be set. If the ignition wiring were being stretched from engine torque at WOT and interrupting ignition circuits, you would get misfire and poor spark energy, and set a code 12.

Just a couple of thoughts.