I found today that the trans fluid was below the fill line, so I added what little ATF+4 I had on the shelf and brought the level up to “add.” We’ll see if anything changes after I get more and top it off.

 

Topping off the fluid helped a lot, but the problem is still there. It just doesn’t happen as often. That solenoid job will be added to the list.

 

I have not fixed anything yet, but I have found another part of the problem. This issue only happens while cruise control is engaged, not when I’m actually working the peddle. Any ideas and what to look at?

 

Cruise servo and gas pedal do the exact same thing, open the throttle blades, and move the TPS.

Try the test I outlined back in August. Let us know what it does.

 

I thought so. I just tried it one night and it happened all too often with cruise on versus not at all while using the peddle, so it got me thinking.

 

Cruise is computer controlled, and it will make little adjustments to throttle position even on flat roads...... Your foot isn't quite so active.

 

My truck does the same in certain situations like going up a slight incline on cruise control. I believe it has to do with the way the cruise control works in these old trucks, it is vacuum operated and uses two solenoids so it tends to make very small throttle adjustments at constant speed. With an old throttle position sensor the PCM sometimes thinks it needs to unlock the torque converter clutch to get back to the set speed. I've been debating replacing the TPS but it doesn't bother me enough and with the junk that parts stores have on the shelf nowadays it might not get better.

 

Do you have a DVOM meter? Set the meter to AC volts and measure across the battery posts with the engine running, anything other than 0 is bad alternator diodes and they will cause TC issues

 

Good to know. I’ll check it out.

 

Thanks for the replies, guys. I’ll probably add a new TPS to my next rock auto order and try that out after testing for AC interference.