As the title states, it surges or "Bucks" between 1900 and 2100 RPM when I give it more than 1/4 throttle.
This just started happening on friday.

Throttle position sensor?
Cam sensor?

Other?
Any help with this would be really appreciated!
2001 Jeep wrangler, 4.0, 5-speed. 109,000 miles.
Jason.

sounds like the throttle sensor

check engine light on?

by surges, do you mean it looses power for a second, then returns to normal?

Could be the fuel pump. They tend to act up intermittently when they begin to fail.

No check engine light. It pulls fine up to about 1900 RPM then loses power for a second, then has power again, then loses power... This happens about 3 or 4 times between 1900 and 2100 rpm, then seems fine til I shift, then it happens again around 1900... It does this in all 5 gears. Always (And only) between 1900 and 2100 RPM. It isnt intermittant, it does it every time without fail, weather its cold or hot. Feels like when someone doesnt know how to control the clutch and makes the vehicle "Buck"... It's pretty violent. (Enough that people who are riding in cars near me notice it and give me funny looks.)

The guys at my work (Mechanics) are full of Ideas: Throttle position sensor, crank position sensor, o2 sensor, MAP sensor, plugged cat, Bad fuel pump, etc. If I listen to them, I'll spend around $250.oo and still possibly not find the problem,,,

I had a similar issue with mine and it was the throttle position sensor

maybe try swapping it and if it doesnt work take it back to autozone?

Thats kind of the direction I'm leaning in... Worst come to worst, It wont cost a fortune...

If it really ONLY happens between 1900 and 2100, I would say there is almost no way it would be a bad fuel pump, clogged cat, or O2 sensor. I know my fuel pump is going out. It does the same thing as yours except doesn't care if it is at idle or WOT. I'm with Chris on the TPS.

I hope it's not the fuel pump. If I replace it, can I use the later '03? to '06 high-pressure pump? I'm going to be swapping to an LS-2 soon...

So... did you find the solution? I enjoy reading this tech section and learning about what the solutions are to the problem.

Not yet. So far I've replaced the throttle position sensor, o2 sensors, crank position sensor, coil pack, injectors and fuel pump. no changes so far...

that stinks. I know this guys far from you but Gregs done a great job of diagnosing and fixing a lot of our rigs

http://www.higherground4x4.com/forums/showthread.php?4199-Greg-s-Value-Auto-Repair&goto=newpost

I may have to go there... A new problem popped up this week: Got a vapor leak. The check engine light came on and the code reads "evap system leak, small" and "evap system leak, large" I can probably fix this one myself. (No, it's not the fuel cap this time.) I can smell the leak, but so far I cannot find it.

This article is primarily for Cherokees, but since they share a common 4.0 with many other Jeeps, I would think the troubleshooting would be very similar for most applications. I have found this article to be most informative and it, with the use of a digital multimeter, has helped me pinpoint the problem most every time, without having to replaice by tiral and error.

Basic Sensor Diagnostics

Thank you! I'll check that out!