You mentioned the TPS. FWIW, I had a “late” shifting issue on my ‘91 which transformed into a “no shift” issue at some point. I forget the details now, but after researching a bit I swapped in a new TPS and this solved it. I must have done the calibration as part of the install. Worth looking into.

 

my issue turned into a no transmission issue for 10 minutes, I honestly have no clue how that even happened but I was trying to use 1st to slow down going down hill and then the transmission lost all gears and started making a horrible grinding noise in every gear except park which didn't keep the car stopped. I shut off the car and called someone to come up and rescue me, then in an attempt to get out of the way or roll to a wider spot in the road, I turned the car back on and magically no transmission problems. I did swap the TPS but as I've read further on newer XJs there isn't a calibration for the TPS.

 

Update I've decided to post up the engine codes/issues I have up in hopes of maybe some are related and I need to get them fixed, but I have engine codes Po700, Po7C0, Po135, Po141, Po141, P1491, and P545 (Only reason I didn't pull earlier is right after installation there was no codes and come to find out the check engine light is burnt out so I had no idea the light was supposed to be on). Along with that my steering wheel turns on the dome lights when I am turning, at a certain point it starts turning on intermittently but at full lock the dome lights are 100% on. at around 25-30% turn it starts flickering but goes off once steering input stops being changed.

 

Forgot to mention my cruise control is nonfunctional

 

Alright guys I fixed the light issue, it just had to do with my door latch bolts being loose and falling out, but still has the shift issue, Again P07C0 and P0700 are the only trans codes present, and I have not found any clear answers for what P07C0 actually says is wrong. Please if anyone has any suggestions I really need anything that may fix it at this point.

 

Are you brake lights working? If the brake lights are stuck on, that will prevent both the cruise control and the torque converter lockup (what you may be calling 4th gear) from engaging.

 

The common point of failure for a lot of that stuff is the ground under the driver dash. The dash assembly doesn't get grounded to the rest of the body very well so I run a ground strap from the dash ground point to the a-pillar, of course sanded shiny. Sounds like your dash harness is finding intermittent grounds through other circuits. The wiring harness diagrams on jeep-manual.ru show the grounds.

 

Brake lights are working properly

 

@HicksCME where is the dash ground point normally located? That is my only guess for a wiring issue, I've dug around and have found no wierd spots or anything that would signify wiring problems.