So the car is an 88 vert with a s4 t2 motor in it. The harness is being repaired and im hoping that will help with some of the question. The idle is very high about 2k, so i wanted to adjust the tps sensor. when i do let the engine warm up to try and get it off the fast idle cam after a little bit it starts kinda surging and not sounding so heathy then it soiunds like theres a popping in the actually combustion chamber this scares the **** out of me so i turn the motor off. Has anyone expierenced this? anyone konw what it might be detention? preignition? I think the timing might have been messed with you can see scratches on where the nut can move on the CAS. I wanted to check timing but shouldnt you set the tps first? The temp gauge doesnt seem to be reading right im gonna test the sensor and hope that the new harness fixes that problem. ps new fuel filter and the injectors were just cleaned.thanks again guys been so much help....Brian

 

dunno about the popping exactly, check your timing with a timing light and adjust your CAS position as needed. Then adjust the TPS