is it the fuel pump??

i have a 87 xj 4.0 auto 240k, i have noticed that at times it is slow to start, and latley after it had been running long enough to get up to temp if i cut it off it will not start back. it will turn over and sometimes start but it will just barely idle and then cut out, happened a few weeks ago so i first thought pump or even filter, so i changed and still slow to start or spit sputter and die once warm and cut off.. friday it cut off by itself, gayge had half tank, i tried to recrank and did the same spit sputter die, then the gauge swung all the way past full and hasn't moved since, what should i check first??? thanks in advance

I vote fuel pump, mine was running very erratic and hit and miss like yours and it was the fuel pump.

It could even be the ground connection at the fuel pump module. That could affect the pump and the gage.

winterbeater said:

It could even be the ground connection at the fuel pump module. That could affect the pump and the gage.

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is that located on the tank or where at??

I have an 89 and have had the same thing happen,I was driving it and it just quit,start it up sputter and quit. it was the ignition control module under the coil,it was just old and when it got warm it quit,I assume from high resistance once it got warm. it finally just quit. It also happen once due to the coil.
I now carry spares

thanks for the response, i might try to look at it a little more this evening, if it was the ignition module could i rule it out by pulling a plug or wire and looking for an arc? is there a fuel pump relay i could check? and what causes the fuel gauge to malfunction? will any of this have anything to do with the ignition switch?? i had problems with it a while back....

Shorty01GMC said:

thanks for the response, i might try to look at it a little more this evening, if it was the ignition module could i rule it out by pulling a plug or wire and looking for an arc? is there a fuel pump relay i could check? and what causes the fuel gauge to malfunction? will any of this have anything to do with the ignition switch?? i had problems with it a while back....

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When this happens check for spark,if you have spark then I would say that the module is ok. You may want to pull your pump out and see if the suction screen is bad,there is also a small rubber line from the pump to the outlet that could be bad,have you checked your fuel pressure regulator? The fuel pump relay is located next to the coil,I am not sure which one it is but I recall someone saying it was the second one in.
Also on your left front fender inside the engine compartment is a porcelin connector with a single wire going to and from,I am not 100% sure what it is for,but if it is loose or comes off,your fuel pump will quit,had it happen many times.
Hope this helps