Blacktop 20v issue... opinions?

[full_lock 86]

ok so alittle background info first. the previous blacktop i had installed on my 86 was getting old and started to lack power (as in still ran smooth but didnt seem as fast as it used too..) so i bought a new 20v from a friend that was rebuilt. basically swapped my water relocation and a few sensors and swapped in it. so its not the ecu or harness

what its doing is back firing and falls on its face for a few seconds then takes off like normal. ex: 2nd gear holding the rpms at 4k then hit the throttle and it will back fire and pop and sometimes even make no noise at all like it stalled completely then goooo.

whats weird is that the problem is alot more acute right when the car reaches operating temperature and kicks the idle speed down..

idk what it could be, i checked tps, timing, tested vvt solenoid, only thing i can think of is if i messed up on the tps but i followed the 20v manual to the dot and set it multiple times...

any opinions? maybe FPR?

[onnaj]

Maybe too simple, but changed the ignition wires somehow? Or one of them is bad?

[full_lock 86]

Anymore opinions?

[NikNes]

It sounds like you've check most of the stuff. Did you check for potential vacuum leaks that could be affecting the MAP sensor reading?