jmurdock45

Okay we will ve driving on the road and out of nowhere stopped or driving she will die if I let off the gas she starts back up but then dies shortly after any ideas

Roler

We probably need a bit more info, as there are several pathways to go down on in order to find the cause.
Is it that you are cruising along , and the engine stalls or just cuts out without sputtering/warning? Is starting an issue. Is it intermittent or all the time?
Any other associated symptoms, like loose lights/gauges?
Things like tune-up, grounds, CPS, fuel delivery etc etc ; all of those are on the list too.
Start with a bit more info.

jmurdock45

Well I'll be stopped and it acts like she's running out of gas and sputters and dies or sometimes just dies without warning

VTJeep

o2's, possibly fuel delivery. Put it on a code reader before you spend any money trying to troubleshoot a problem. Could also be something with TPS, IAC valve or maybe a bad ground..

F1Addict

Sounds like your Crank Position Sensor (CPS). Are you mechanically proficient?

Roler

x2 (as stated).
CPS could well be a cause (and not always throwing a code) and at some point, it WILL fail in the life of the 4.0 and if not yet addressed, now is a good time to replace it with a quality one, might well solve the issue, and if not, is off your things to do list for future reference.

Located on the left side (your driver side, my passenger side up on the transmission bellhousing (will need some extensions put together to reach it).

Let us know how you go.

mud'njeep

Very true

F1Addict

When my CPS began to fail it exhibited the exact same symptoms, it sometimes sputtered and hesitated as if it were fuel deprived, stalled randomly and would sometimes restart with a simple turn, other times I had to let it sit for a few minutes. Sometimes it would start and idle normally but as soon as I pulled out of the driveway it would die. Eventually, it refused to start and the kind folks here directed me straight to the CPS store.

As Roler said, replacing it is good preventative maintenance because it will fail. It's only a pain in the butt the first time you attempt it. I can change one out in less than 5 minutes and barely get my hands dirty but that's because I've done it more than once. Why more than once you ask? Because I thought I'd test my work before buttoning everything up and forgot the all-important step of strapping the lead wire to the harness where it passes by the exhaust manifold which resulted in a smelly, melted mess of plastic insulation just seconds after starting. If you attempt this yourself, don't forget that step

jmurdock45

Well I think I fixed the problem water in the fuel.. who would have known I replaced the filter and put some stp fuel line antifreeze and water remover and it runs fine

jmurdock45

It's back again where is the cps

F1Addict

You know, I replaced my fuel filter and that seemed to fix it, too but it was just that I had let it sit long enough that it would restart. As soon as I put it in gear, it died.

The CPS is located near the top of the bell housing (driver's side) where it attaches to the engine. You'll need some extensions and patience to get to it. I've found that going in feet first from the driver's side puts your arms at a much better angle for getting up there to remove the bolts. I was very lucky to have a 30 inch extension, you'll need about that much to get to it. Be careful to NOT drop the bolts in the bell housing, that's bad news.

Here's a decent write-up...

http://www.go.jeep-xj.info/HowtoCPSchange.htm

sik_xj

Quick question. Would a CPS be the culprit of a rough idle if it idling for long periods of time, and take a few cranks to get it started?
I have done everything under the sun with the exception of replacing the cps and the exhaust manifold to try to solve this issue.
I sometimes also get a brief check engine light code for a misfire, but it goes away.

and my other question is that some places sell a cps for like 75 bucks (seems like the going rate) but I have seen them as low as 20 or 30...is there differences between the cheaper ones and the more expensive ones? To my understanding there isnt a whole lot to the sensor.

Sorry to thread jack...I figure the OP and others could benefit from this info and I didnt want to start a new thread for just that.

Roler

Rough idle can have several causes, and it depends on what you did so far to solve it ("everythng under the sun"). Checked the codes further? Only rough idle or also stalling during ride? Rough idle when cold and hot?
And yes, ur CPS can also have an influence on these things.

So, like stated before, replace it with a good quality one (am not uptodate with US prices) but dont cheap out on this vital thing, it will be worth it not having to think about it for a few years and at some point in its life it WILL leave you, so get it done with. Cheap sensors sometimes fail within no-time.

sik_xj

I figured you get what you pay for. The code that I pulled was a p303 I think. I know it was a misfire on 3. I have done plugs, wires, cap, rotor, every sensor on the throttle body, cleaned the throttle body, etc etc. like I said the only thing I have not really checked was the CPS and replacing the exhaust manifold. I have never stalled, however once my jeep is started after a few cranks it idles extremely rough for about 20 seconds then smooths out. And idles rough if it's been idling at a stop light or something for a few minutes. I have no issues whatsoever when driving.

VTJeep

Still say make sure o2's are good and the fuel delivery isn't impeded. Try checkin fuel pressure at rail when issue acts up?

Edit- I've heard the clock spring can effect idle as the TPS grounds out thru it! Is airbag light on and/or horn not working?