2001 Surge and Shifting Problems

[K5hart]

Hello. Brand new here so thank you in advance for the help and the information I've already been able to pull from this site. I recently purchased a 2001 with the 3.5 for my son. It had problems right off the rip. I have replaced the ECM with a refurbished one, changed the IACV because it was bad, the TPS sensor, and the MAF sensor. I did the IACV relearn using my laptop with NISSCAN II software and set the TPS using it as well. The truck runs fantastic if I leave the Throttle Position Switch (Grey Plug) unhooked from the TPS sensor. If I plug it in I get a surge in Park if I rev the engine to around 2000 rpm and hold it there. Kind of like a rev limiter is the best explanation of it. I get the same surge when it shifts from 1st to 2nd gear and a transmission flare from the 2nd to 3rd shift if it's under very light throttle. If you give it just a bit heavier throttle it doesn't do either of the shifting issues. I've checked vacuum hoses, tried 3 different TPS sensors, another IACV valve, a couple MAF sensors, fuel pressure regulator, and verified the swirl valve solenoid worked. Nothing changes the problem. Has any one experienced this? Does anyone know what I'm hurting by driving it without the grey plug connected to the TPS?

 

Thanks again.