Jeep wont start. Jump it and it'll run but will die below 1k rpm's. Whats up?

In addition to having $1500 stolen from my XJ it also decided to not start after work lastnight. Its a 96 Auto.

The door chimes nor the radio lit up when I opened the door. I knew I was in for a surprise.

I thought it was just a dead battery. I came back to work this morning. and tried to jump her with my GF's Lexus. It didn't want to hardly turn over.

She rev'd up to 4k and I finally got the XJ to crank but it wouldnt fire. I once then pumped the gas a few times and tried again. The XJ started but I kept the RPM's at 2k and when I let off it promptly died.

I then stubbed my toe on a parking barrier and tore my nail off. I gave up.

Im thinking its possibly the fuel filter? I didnt think you had to pump FI systems. This is my first transportation without a carb lol.

Any ideas guys?
Thanks!

i'm gonna guess - bad battery. when it runs at 2k but dies at lower rpm i'm thinking it is running off juice the alternator is making, then when you let the rpms drop the battery doesn't have the cajones to keep her going. that's assuming your cables are clean/tite.

^They are, Ill swap out the battery and see if that helps. Thanks for the idea!

Otter said:

i'm gonna guess - bad battery. when it runs at 2k but dies at lower rpm i'm thinking it is running off juice the alternator is making, then when you let the rpms drop the battery doesn't have the cajones to keep her going. that's assuming your cables are clean/tite.

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I would guess a bad alternator before I would say the battery is bad. A battery is really only used to start the vehicle and once it's running the alternator should provide all the power it needs. If his alternator crapped out the last time he drove it, he could have ran the battery down. Now the battery doesn't have the juice to start it, and the alternator doesn't have the power to keep it running.

An easy way to test for a bad alternator is start the vehicle and disconnect the battery, if it dies the alternator isn't doing it's job.

The fact that you have no chime or radio/lights without it running tells me the battery is probably dead, and the fact that it doesn't run when you disconnect the jumper cables tells me the alternator is probably bad.

I had the EXACT same issue after a dead battery. apparently, if the battery gets completely drained, there is not enough juice to run the fuel pump....thus, your jeep only runs with your foot on the gas - at idle, it dies.

just run the jeep revving a little for 20 min...if then you still can't run at idle, you have an alternator problem.

Take Battery to autozone. ever cleaned your connections?

It's your battery. Or connections.

Replace your battery first. It's cheaper. It probably has a dead cell in it.

What got stolen?