Quick run down: i just bought a 2000 z28 with a 6.2L, lS3 heads, LS3 intake, 65# zr1 injectors, nick Williams 92mm throttle body, 224/230 580/580 114+3, long tubes, lid and I was told a base tune.my issue is, sometimes the car runs great but other times it stumbles like its "loading" up and then back fires and feels like it's going to die but it never does. I hooked a scanner up to it and i monitored the tps values and this is where my problem is. I'm supposed to have a .68 reading at idle and when i accelerate it should climb to 4.8 correct? Well Mine shows .00 at start and then the values climb in .02 increments until it reaches 5.0 and then resets to zero. When it's at 2.4 and up the car runs fine but when it resets to 0 and it's below the 2.4 it runs like crap like i stated before. I swapped the tps with a new one, same problem. I checked the connector and I have my 5 volt reference, signal and with the car off it moves with the throttle body reading, but when the car is running or key on the computer is doing the .02 increase the whole time......I am LOST. any ideas? Ill post a video of the tps with the car running in a minute. Thanks in advance!

 

Car was idling the whole time

 

Have you tried a TPS relearn? Also double check for any vacuum leaks.

 

No vacuum leaks. And to relearn: unplug sensor turn key on and off three cycles then plug it back in and start it right? If so I did that

 

Maybe, try the tune /diagnostics forum????