TPS question

[BWMJ]

Ive been having some trouble with the MJ pretty much since I bought it. Every once in a while it would act up and hesitate, stumble, etc. Recently I disconnected the EGR system. This seemed to help a lot. For about a week the truck didn't act up and then one day it would hesitate at about 1/4-1/3 throttle and you couldn't give it any more throttle past that or it would just shudder and hesitate. This has happened before, but always cleared itself, and I thought that it was related to the other issue that I was having with the truck starting to hesitate after warm-up to the point I'd have to pull over for a few minutes and it would clear itself (This went away after disconnecting the EGR). Well, the 1/4-1/3 throttle issue hasn't gone away since it started about 5 days ago.

 

This morning I went out to test the TPS as per the instructions I found in numerous places. I got an input voltage of 4.04 volts and an output of -0.78 volts. when I tried to adjust the sensor, the numbers would not change. What's going on? Does this just mean I need a new TPS? Any thoughts are appreciated.

[SaltyMJ]

Not sure if this will be any help...but I had a similar problem with my Tj..I had replaced the tps numerous times because I was fed up with the problem lol..turns out it was my o2 sensor. After putting a new o2 sensor on I haven't had that problem since. Try disconnecting the wire to the upstream o2 sensor and see if that helps.. When I tested my tps sensor the instructions said to watch the volts as you slowly open the throttle with your finger and the volts would go up gradually...I think it stops somewhere around 5volts..Hope this helps

[fiatslug87]

Since the output voltage should be 83% of the input for the automatic TPS, I'd say you need a new one. Lucky for you the auto TPS are much less expensive than the manual ones. From the RENIX manual:

[BLHTAZ]

Based on your test results, and the fact that the voltages do not change when the TPS is loosened and moved, I would say that you need a new TPS. The o2 sensor may be a good thing to change as maintenance if you don't know when it was last done. o2 sensors are a regular maintenance item and should normally be changed around every 60-70K.