Hi all. I've got a 94 3.9 with a tps problem. It shows all the classic tps symptoms. Surging at timesa couple hundred rpm, hesitation on acceleration, hard to get over 2000 rpm, tranny doesn't want to shift.
I changed the tps, reset the brain and the same symptoms persisted. Figured the new sensor could be bad also, I got another one but a different brand. Did the reset same result. Checked the voltage at the tps and all readings were within normal ranges. What am I missing? What else could it be?

 

Vacuum leak is another choice.

Since it's a 1994, have you checked the plenum gasket? That is, with the motor NOT running, remove the top hat off the throttle body, manually open the throttle body, and looked down into the intake?

Also, how long since the last time plugs/wires/cap/rotor have been replaced?

RwP

 

I cleaned throttle body and iac, new plugs and wires about 30000 miles ago. Found 2 vacuum leaks, fixed them, no change.

 

So. How's the bottom of the plenum? 30,000 miles - might be time again, especially if the plenum has failed and it's now fouling plugs.

RwP