I have a 1991 xj. It'll idle in park and drive all day long no problem. Sometimes while driving down the road it kinda cuts in and out almost as if the "fuel suplly just stops". Like my fuel pump cuts in and out almost. When i leave a stop sign or stop light it sometimes dies and takes a minute to start back up. If i can save it from dying, i throw it in neutral no matter where im at, and hold it to the floor to kinda "clean it out". Its almost as if either the fuel lines are clogged or something is wrong with the fuel pump. Any ideas?????

 

What engine do you have?
Have you replaced the fuel filter? Also, you should check the fuel pressure at the fuel rail.

 

Its the 4.0. Changed fuel filter and good fuel pressure. 49psi at idle. The only time it cuts out or stutters is while driving and its the worst when i try to take off from stop. Sometimes cuts out while cruising at low rpm. But doesnt always do it. I had the same exact problem with my previous xj. I do not remember the exact cause but i do know that it is a fuel problem

 

That's a common symptom of failing pump. PSI isn't CFM--the volume required to maintain idle is much less than the volume needed for 2000 RPMs.

Its also a common symptom of failing crank sensor and/or cam sensor. The injector timing is controlled by the computer based on the ignition timing signals, and if either of those sensors start cutting out then the fuel and spark will both cut off

 

So should i check out my pump first? Or should i check the sensors?

 

Also make sure cps wire are not touching any where at rear of engine.

 

Something else I just remembered, some people have trouble with the rubber hose inside the tank coming loose.

If you want to eliminate ignition problems, see if you can find a mechanic's stethoscope somewhere (NAPA, Harbor Freight), then use it to listen to the injectors the next time you have poor revs. You should hear a steady click click click noise with each injector, and will be able to notice a miss. If ignition is fine and its still stalling, then its probably fuel related.