Lou4130

Ok so what i observed with my shifting issue is that every other time i start my XJ, the transmission shifts pretty much like normal when driving. Hangs up a touch from 3rd to 4th, but it does switch to 4th. So basically, if it does this, and shifts fine, the next time i start it and drive, it will get hung up in third. So what i have been doing is driving to a close gas station, pulling into it, shutting it off, then restarting and getting back on the road and then its back to shifting fine and making it to 4th (still hanging a little bit in 3rd). So myself and a few folks i know think its an electronic issue not a mechanical one since it is consistently inconsistent. We feel if it was mechanical it would happen all the time or just randomly. So, it was suggested that it could be the TPS. So i got a Dorman one cuz a buddy had a brand new one on hand, and it is still doing the same thing but now it starts really rough and takes a couple minutes to smooth out. ( i would have put the old TPS back in but my dumbass threw it out by accident) it did this rough start/idle when i first got this XJ, and i thought it may be a fuel issue, since it sat for a bit before i got it. it starts rough and the idle drops and goes back up almost stalls but doesnt, and it sounds like the cold air intake is sucking very strongly. Once it runs for about a minute the sucking sound fades and the idle goes pretty normal. Once at temp it runs fine. i had put seafoam in it and it seemed to run great after that. Started on the first time almost every time, and no rough idling, even from a cold start. Since i changed the TPS, now its doing this rough start again pretty much exactly the same. I have a used MOPAR TPS on the way so im going to swap that in in case its because its the Dorman TPS. I know these Jeeps dont like Non OEM/Mopar stuff, but since it was free and immediately available i figured id try it. I also have a TCM on the way im borrowing from a buddy to see if that is the cause of the shifting issue. If it fixes the issue i will buy it from him, if not, i'll just send it back to him.

So any of you guys have any other ideas what the shifting issue could be, and if the sudden "back to rough start" is possibly the Dorman TPS? though i never changed a TPS before, it seemed super easy and after a few youtube video watches, Im pretty sure i installed it correctly as i know its spring loaded. I put it on slightly tilted to the passenger side and then turned it to the driver side to make it straight and installed the screws.

Very Red XJ

This drawing depicts the duel wiring for the engine management (ECU) and the transmission management (TCU) note they are indirectly connected. The transmission wiring runs along the firewall of your Jeep. The TCU is above the gas peddle mounted on the consul bulkhead and it seldom fails. If all the wiring is good (not frayed, damaged or shorting out and the grounds are good) check the sensors with a VOM. I push pins into the wire and grasp the pin with alligator clips wired to the VOM. A faulty sensor sending to your TCU could be intermittent - heat can effect the sensors. Look at the wiring on the drivers side of the transmission if you haven't already done so.

Very Red XJ

I have a K&N filter too - you need to buy the kit from an auto parts store to clean it and add fresh oil correctly. The single hose clamp around the throttle body frequently comes loose - so check that it's tight. Get a shop manual, a VOM and TEST the sensors rather then blindly replace them. This is my drill, because I'm bad at guessing - get your shop manual. Assuming your air filter is clean, spark plugs, cap & rotor and wires are good, check for dangling wires grounding. The wires coming up from the O2 to the fuel rail wiring harness are a good place to start. Then open your shop manual and test your sensors: the temp sensor, idle solenoid, MAP and TPS. In my experience, the crank position sensor is good - or you stranded by the side of the road - but test it anyway. If they are good and your throttle body is clean, move to the injectors: clean them and test the resistance for each one. You can pull them and use a 9v battery to produce a click unless it's defective.