RICEFEDZ28

Does anyone know if I need to have pcm programed to add a larger throttle body on an automatic trans car? I put it on once before and it caused my trans to shift really late and stay in 2nd. I put stock one back on and everything is fine. Is there something special needed to be adjusted? Any help would be great.

LJ93Z28GM

Likely your TPS is not set correctly you need to open up the mounting holes so you can adjust it and check the voltage at idle and WOT by checking the wires that fed the sensor.

Your car might believe it is not at WOT even when you are. The car believes the pedal is in a different spot than it actually is. Most common problem on them. Had to do it on mine. Not hard to do at all just need a meter and some of your time and patience.


At idle it needs to be at .3 to .9 volts in the middle is best some years will throw a code or do odd things as yours. WOT is suposed to be about 4.8-5.0 volts.

plan Z

i'm having kind of the same problem. i've been trying to adjust my tps everywhere (from .4 - 1.0 v) and most of the time my problem is its shifting way too early. once or twice i got it to do the opposite and shift late like you are. but then when i readjust it back a little, it shifts too low again. when i had it set at 1.0 v, the tps% was actually 1% though so i guess thats too high. can i adjust any of the tables when tuning my car for the torque converter engage/disengage and the shift points? should i just set the tps to like .6 or .7 and then try to start tuning?