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Hopefully you guys can help me figure out the next step in troubleshooting this issue. The engine revs just fine when in park, but driving on flat ground, it stops accelerating at 35 mph and starts to sputter if you give it more gas. It will go over 35 and shift into 3rd if you get going downhill, but as soon as you go back uphill you lose power again. I was hoping it was just a plugged cat, but I unbolted it and still had the same problem. I’m assuming it’s a transmission issue but I’m not sure how to diagnose it.
I’ve replaced the fuel pump and filter, plugs, wires, ignition coil, and crankshaft sensor. Any advice would help.

Chick-N-Picker

Two things to do.

1. Check your brake light switch. It is located up above the brake pedal. Make sure the plunger is not stuck closed. Had two jeeps where those got stuck, an 89 and a 94. It caused it to drive fine until exactly 35mph then it would lose power and shutter. Not death wobble. That switch controls the torque converter locking and unlocking.

2. You can unplug or pull the fuse to your transmisson control unit (TCU) and shift through the gear manually. 1, 3, 4 (OD). If it shifts and does fine then you can rule out any mechanical issues. The TCU and the fuse is behind the driver side dash.

If you can not find the location of either one of these by searching, then let me know and I will help you by posting pictures. You should be able to find it by searching "TCU location cherokeeforum" and "Brake light switch location" on google respectively.

Chick-N-Picker

Screw it. I found it for you anyways. Below is the fuse and TCU location. Unplughing the fuse just to test shifting will be fine. If everything works after that let us know and if not we'll go from there.