lfhoward

I was wondering if anyone knows what might be going on and how to fix it. My 2000 XJ 4.0 worked fine until this morning. Now when I start it and put my foot on the gas it'll rev fine. When I take my foot off the gas it immediately shuts off. It won't idle at all. No sputtering, just cuts completely out like I turned it off. Any ideas? Thanks, everyone!

kbad

any codes? does it crank and start up without giving it any gas? any leaks around injectors/intake manifold? perhaps fuel system/pressure issue....start with fuel filter, then fuel pump,.... line, rail, injectors, etc.

lfhoward

Thanks, kbad. I went outside to get the answers to your questions and here's what happened. There are no codes. The first time I started it up, it seemed to catch for a second, then died. The second time I started it up, I gave it some gas and held it for approximately 30 seconds, revving it up to 3.5 or so every so often. At first it would begin to die when I let off the gas, but after a while it seemed to hold. Now it seems to work fine, idling like a champ. I can shut it off and turn it on and it works. Maybe it just threw a fit because it wanted attention?

kbad

.....could also be CPS, IAC valve or TPS acting up/ready to fail!

hope it was a one time hiccup.....know what you mean, my jeep's been running great (knock on wood) but it's been garaged cause i've been messing with my daughter's car and the other day it threw a viscous fit until, long story short, i cleaned up the intake, better, not half-arsed AND purged the egr! now, it's a happy roaring I6 champ , again!

you know, you can beat the crap out of a jeep, but if you ignore it, it will seek attention - hello Christine !

Colinjohns

Did your battery die...if it did mine likes to do what your describing when that happens. Just hold it at idle or drive it around for a bit and it will stay on for you.

lfhoward

Thanks Colinjohns and kbad-- I think the battery is fine, as it cranks and starts the Jeep up fine. I will see if she keeps running without any more hiccups, as I will be taking her for a short trip this weekend, and keep you posted. Do you think this is worth a preemptive visit to the mechanic, or would you just keep an eye on it and hope for the best?

kbad

cranking battery doesn't mean it's a good battery! if the battery's continuous voltage drops to below set parameters, i believe 13-14V, then it will still seem fine and dandy, but really, every electronic component that uses the voltage as reference will be affected and miss lead you into other issues....i "thought" i had good battery, within warranty, etc., but sure enough, it was the culprit (Continental battery) - now i have a high crank Interstate - no worries!

batteries are funny, not ha ha, opposite! ....older ones specially, tend to act up as they get hotter.... in the south, they tend to fail in about 2-5 years....if you know yours is good/new, then you should be good to go....if you don't know for sure and may end up stranded, swap it out for a brand new one, take the trip and see how it goes...worst case, you have a sure thing with a new battery and will know that it may not be the problem if it happens again!

tuxfan212

Take the battery and have it tested at a auto parts store. My friend drove his dads van to school he left the lights on to kill the battery and we had choke it and then rev it continously to keep it running. His dad ended up driving it home and after that it was fine.

lfhoward

I thought I would tie up this old thread of mine by posting what worked. If a solution is posted, then maybe it will help somebody else who searches the topic.

To recap, my jeep sometimes turned itself off at idle, and when this happened, I only could keep it running when I held down the accelerator slightly to give it a little gas. The problem was completely solved after I carefully removed my IAC (idle air controller, I believe) and cleaned it using throttle body cleaner and an old toothbrush. It was pretty carbonized. I took the opportunity to clean the carbon out of the throttle body at the same time, since I had it all apart. (Note: be sure to use throttle body cleaner, not carb cleaner because that's too harsh.) After doing this cleaning about 6 months ago, I have never had it act up again. Idles like a top.