Running and Shifting Issue. Help Guys!!!

[chevrock22]

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.

[fredjacksonsan]

Welcome to Jeep! Once you figure out your buggaboos, you'll enjoy.

The 4.0 is a great powerplant, but is prone to a couple of issues. One I harp on is the Crankshaft Position Sensor (CPS), and the Throttle Position Sensor (TPS) is also to blame for numerous glitches.

If you do a quick search on these two items, you'll find lots of issues similar to yours. If they don't do the trick, post back and we'll try to help out.

Also, what year and how many miles? That info's always helpful.

Finally, check your transmission fluid to be sure it's at the correct level.

[chevrock22]

Ill have ya know, it was a t.p.s. switch. All done. ready to go.