Nubflex0r

Engine has 2k on it, fires right up, purrs great, responds great, drive for 10 minutes on freeway (up to operating temp) at ~2500 rpm and then it starts to buck and shake the whole jeep like a fuel/vac issue. Cruise to a stop, pop into neutral, rps freak out from about 500 to 1250 a few times, then calms down to 750 and it's fine again for a few more miles, then doe it again. Retightened my intake manifold and checke for vacuum leaks with starter fluid. All seems good. Brand new fuel pump already bad/overheating? Been like this for about the last 100 miles (16 miles round trip to work each day). Nee diagnostic help.

cruiser54

Thanks for your post.

We’re here to help, but you must understand that all Jeeps are not the same.
In order for us to give you more accurate advice and help, we must know the following, as applicable, along with detailed information as to the symptoms/problems etc:

Year
Model
Engine
Transmission
Transfer case

firehawk618

^ That is the absolute politest way to say WHAT YEAR IS IT!??

Parsnip

Year motor and trans please

But my earliest shot in the dark guess says o2 sensor possibly, mostly due to it warming up before failure.

But give us more info first

Nubflex0r

92, 4.0 HO, AW4, 231. Jeep has ~250k, but i gutted everything and redid everything except tranny rebuild when i rebuilt the engine. 5 ish inch lift, WJ front end swap, 33s, new fuel delivery system (pump, hoses, injectors [4 pin]), new header, new 02 sensor, new intake, rebuilt 231 with sye. Everything has about 2 - 2.5 k miles. Let me know if i missed anything else relevant. Thanks (: