I’m inquiring about the mass air flow sensor I guess the reason why I am thinking it could be something that I need because the engine revs high. I don’t know exactly how much because my tachometer is not working.

 

If you have a GEMS vehicle, then high revs happens when the TPS is mis-adjusted (TPS signal is higher than baseline in idle position). Resetting Adaptive Values will fix, or adjusting the TPS. This is for if revs very high on start, but normal when put in gear (auto transmission). What year is your truck? PS. One way to check the MAF is to unplug it to see if the problem goes away.

 

Mine (98 v8 auto) was reving high when in park/drive/reverse. - I replaced TPS and IACV - did not replace MAF (or unplug it). It was still reving high. Resetting adaptive values is what fixed it.

In my 98 v8 auto, tach is fed from alternator. Is your alternator working? I dont believe this would have any effect on high revs though.

 

The TPS where is that and how do I adjust that? It’s probably something I already know, but I don’t remember.

 

It’s a 94 base model

 

TPS (throttle position sensor) is on the front side of the throttle shaft. Check the electrical connector first. Try loosening the screws to rotate a bit clockwise. Maybe try hogging out the holes if need to rotate more (this works for GEMS, not sure for 14 CUX). I notice a replacement TPS is spendy. Make sure the throttle is clean and not stuck open a bit.

 

I had this issue and fixed it the way JohnZo suggested - I chucked an end-mill up in a hand drill and turned the holes on the TPS into slots so I could rotate it clockwise (where looking at the sensor from the front of the truck). It was a lot of cutting but it worked. To stop the issue I had to rotate it until the connector just touched the casting.

For the trucks with OBD like my 97, I could plug in a scanner and read the throttle position. Originally it was 11% and causing high RPM, after the fix it was 1.6% idling just fine. For older trucks I think you can try removing the sensor from the truck but leaving it plugged in - the truck should idle fine like that.