Alright, I first bought this jeep about a week ago. Dont know much about them. It is a 4x4, 4.0L, Auto. It wasnt shifting out of first/second until about 4500 rpm. Then when it would it would sputter shifting into other gears. Really bad sometimes. I did a full tune up, rotor/cap, plugs, wires, ect. Then I had read about unplugging the t.c.u. from under the passenger side dash. It allows me to shift manually but It still sputters/stalls a bit just over 2000 rpm. And thats just annoying. Also the check engine light comes on when this happens. I dont know, this just really sucks. Thanks guys.

 

shifts manualy fairly well. Its still not the way to go about it. Idk guys. just frustrating

 

Could it simply be a really bad fuel filter??

 

I'm not a Guru by any stretch of the imagination, but.... Unplugging your TCU was a diagnostic step, if you could shift well manually with it unplugged, then diagnosing the inputs to the TCU to ensure they are working properly would be a start, and if the inputs check out (IE sensors in their appropriate ranges), replace the TCU. Just my .02c

 

Ya kinda was questioning that whole fuel filter. Im just more worried about the engine chugging. It seems thats why it doesnt shift correctly. I was also thinking it could be that tps sensore or switch.