Gonna jump in here. There are two TPS´s on the 4.0 Engine with automatic tranamission. One gives throttle position information to the TCU (tranny) and one to the ECU/ECM (motor). The posts seem to have gotten them confused a bit. One on top of the other, piggyback, Mr. and Mrs. (or whatever).
The two TPS´s operate the opposite of each other (mirror). A typical value for the Tranny TPS (outer half) might be 4.64V in and 83%=3.85V out (per 88 FSM). A typical input voltage for the ECU TPS might be 4.86V in and .75V (15%) out (the opposite of the trans TPS).
As the throttle is opened the TCU TPS voltage falls and the TPS ECU voltage rises.
If the ECU half of the TPS, varies too far from specifications, it can cause a idle problems and on mine, a very high RPM (around 1800) for a second or two, at start up. The reason for the high RPM (a second or two) at start up, may be the reason for the TPS recall, the interlock saftey recall and seems to be worse the farther the ECU TPS is set from ideal values. My motor may not be typical,as I suspect a small intake vacume leak.
Anyway, the values for the TCU TPS affect shift points. I didn´t record exact numbers. Did notice a 1 volt difference in output voltage (1/2 volt either way from the 83%), seemed to be the acceptable envelope.
Lastly having two different, imput voltages just about makes an ideal adjustment/ratio for both TPS´s at the same time near impossible.
My solution was to split the differnce, shifts a little late (not necessarily bad with larger tires) and idles a little high (not necessarily bad as I idle alot with the radios on).
I tried two different TCU´s with the same output voltages.
A solution to the problem, may be to have the ECU, power both the inputs for both TPS`s. Not gonna try it, what I have is good enough.
Good brain bender for Dr. Dyno.
Could be the same thing, HEKULIINI is dealing with, the TPS, could be OK.
82% TCU TPS/ 16% ECU TPS as recommended by All-Data
83% TCU TPS/ 17% ECU TPS as recommended by the 89 FI FSM
12-14% as recommended by a 17 year Jeep tech.
Ratios may not work out exactly, due to different imput voltages for the different halves of the TPS.
A questionable O2 sensor (or vacume leak) can also cause high idle and affect driveabilty (can fool you) settings for the TPS´s.