When I push my clutch in, like when going from 1st to 2nd, the engine RPM hangs at whatever I revved up to during acceleration before it goes back down to idle. I know it isn't the throttle cable getting stuck. I disconnected it and it feels smooth and consistent. The throttle plate isn't getting stuck; it is clean and lubricated. I just rebuilt my throttle body and thoroughly cleaned my intake and exhaust manifold. New exhaust/intake gasket, new throttle body gasket, new fuel injector, TPS, IAC, MAT, oxygen sensor, all the manifold bolts are torqued to spec and in the correct sequence, and all vacuum lines are tight and without leaks. This is a Renix throttle body on a rebuilt AMC inline 4 2.5L engine. My MAP sensor reads fine with a multimeter. What am I missing? Could the TPS cause the RPM to hang like that? I even reset the ECU with the battery cables touching for 30 sec and headlights/ignition on then off, and thought maybe the ECU was still learning, but it has been a week with no improvement.

 

The tps can cause this if out of adjustment,try and adjust it should help.

 

I adjusted it when the throttle body was off of the intake manifold because its such a nasty spot to get a T-wrench, just checked it again thinking I had bumped it or something during reinstallation. Its as close to perfect as I can get it... still stumped.