Need help with stalling XJ

I've done some searching on site, and while I've found some post with similar problems as mine, nothing seems to be exact.

First, the vehicle in question is a 2000 XJ with about 60,000 miles.


Recently, when I approach stop signs or stoplights, my Jeep stalls. The engine shuts off, I lose the power steering, etc … but my dashboard and radio seem to stay on. It starts right back up after I turn the key, however. This stalling seems to be related to low speeds and RPMs, as it only happens when slowing down.


Whether this is related or not, around the same time the stalling happened, I began to experience sudden drops in speed and RPMs when driving. This seems to happen around 30 to 40 MPH, or when I’m up around 2000 RPMs. I’ll just be driving along, my Jeep will then seem to act like it’s going to stall (jerking me forward in the process), but then the RPMs shoot back up and my speed continues as normal. This drop only lasts for a moment. It feels similar to when an automatic transmission's gears miss.

I also noticed a weird ‘humming’ noise that seems to come from the dashboard. I can’t seem to describe it as anything but an electrical humming noise. It’s not loud at all, but it sounds similar to the sound that comes from power lines. This also doesn’t happen frequently, but I figure it may be part of what is going on, so I’ll throw it out there.

My check engine light isn’t on, but I checked for OBD-II codes anyway and came back with nothing.

I’ll be dropping my Jeep off with my local mechanic Monday. I was planning on driving back home for X-mas, which would be a 900 mile round trip. Obviously I don’t want to take the Jeep if it’s going to get my stranded somewhere. Any advice to possible suggestions to bring up to my mechanic would be greatly appreciated. You wouldn’t just be helping me with my Jeep problems, but you’d also be helping me get home to the holidays!

I’ve read about checking the IAC, CPS, and having the throttle body cleaned as possible solutions. Anything else that could be causing the issues?

Thanks in advance

Job #1 would be to test the crankshaft position sensor. It can create the type of symptoms you are describing (except the humming). A very common sensor fail on the 4.0 Be aware though that it is possible that the crank sensor may test out okay; you could be experiencing a thermal failure (fails only when hot).

I really don't think that this is either an IAC or a dirty throttle body problem.

I myself get the same electrical humming/buzzing noise but only when I use my left blinker.
The only time I was getting really eratic engine revs was about 2 years ago back when I though gas was expensive 'then' and was routinely running the tank on fumes before filling it up. Got explained to me that possibly I was just sucking up the crap and water at the bottom of the tank and sure enough with the gas tank at a healthy level I never experienced the problems again. But that was my unique case.

Fastdemise said:

I myself get the same electrical humming/buzzing noise but only when I use my left blinker.
The only time I was getting really eratic engine revs was about 2 years ago back when I though gas was expensive 'then' and was routinely running the tank on fumes before filling it up. Got explained to me that possibly I was just sucking up the crap and water at the bottom of the tank and sure enough with the gas tank at a healthy level I never experienced the problems again. But that was my unique case.

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The 'humming noise' seems to be an issue after using my 4-ways. I forgot to mention that. I wish the problem was as simple as a running the gas tank too low. I filled up my tank yesterday, and I still had the stalling issue today. I typically don't let my tank go below 1/8th.

Test the CPS. Clean the throttle body and Idle Air Controller.


The humming noise is most likely the blinker relay for the 4-ways. There are 2 blinker relays under the dash, one for turn signals and one for 4-ways. There may also be a relay for the 30 second headlight delay. On my 2000 the headlights shut of automatically 30 seconds after the engine is turned off and the relay sometimes will buzz.

Is it a manual transmission? If so, the rpm drop around 30-40 could be the same thing with the momentum imediately restarting the engine.

Fidget360 said:

Is it a manual transmission? If so, the rpm drop around 30-40 could be the same thing with the momentum imediately restarting the engine.

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It's an automatic transmission. Does this help clarify the issue?

So, at this point, I'll have my mechanic test the CPS, in addition to clean and check the Throttle body and IAC. Anything else that may be beneficial to have them look over on Monday?

Hi,
My money is on the IAC, this is what controls idling speed, if is gunged up the pintle will not be able move in and out properly and it will fail to idle correctly. Hope this helps.