Hey guys I have a issue with my truck it's a 97 f250 7.5 with e4od. I just replaced the fuel pumps end of oct. About 2 weeks ago it started acting up on the rear tank idle would surge up to 1000rpm them drop while the computer tried to get to base idle. It will happen when hot or cold. And sometimes it will die and sometimes it won't. Then it started happening on the front tank. I pulled codes and have a 121 for a tps sensor. Before I go and check voltage settings is there anything else I could be missing..

 

If the issue started on only one tank, I'd go get a fuel pressure gauge and check your fuel pressure.

 

I had a similar problem. Idle would surge to 1200 then down to 500. Sometimes it would die. Got the same code for TPS sensor and another for O2 sensor rich. Tested the TPS and it was in range. Replaced the O2 sensor, no change. Fuel pressure tested good. Swapped AIC with a good one, no change. Can't remember what I did to check the MAP sensor, but that ended up being the problem on mine.

 

Ok so I got a chance to test fuel pressure at idle it is 30-32 psi koeo 42psi. Running with reg disconnected 40psi. Tested tps voltage was 4.1v? Not .9 like I was thinking it should be. I think possibly someone had adjusted it incorrectly before. Anythoughts.

 

4.1v suggests that you probed the 5.0v reference voltage from the PCM.
There is a Green wire and Orange wire. The Black wire would be ground. One of the other 2 should be Signal return and VReference.

 

Nope 1 wire was 4.1 one was ground and one have 5v.o v

 

In that case your TPS has shorted internally.