Solved Stalling while at idle.

[explorerphil]

Hi everyone,
First things first, I am the proud owner of a 2005 4.0L Explorer XLT. I am not a mechanic but I do do most of my own vehicle maintenance and service, the biggest reason is that I like knowing the job was done with care and attention (I may have trust issues). On to the topic of this thread:

A few weeks ago the engine stalled on me at a red light but then started back up right away without issue. While I was driving there was no stalling, performance was good/normal. I continued to drive the truck daily and the problem continued to manifest itself a couple minutes after the engine would get to up to running temp. One day my wife was driving to pick me up from work and she said it stalled every time it was stationary. I went to meet her at the truck and it was in limp home mode I think, It would start and then die as soon as I put it into gear. I ended up towing it home. The next morning it started fine but continued to stall at temperature (the last two sentences may just be a red hearing). Only when it went into limp home mode did I get any codes. The codes were P2106, P0303, P2006, P0621, and P0600. I cleared all these codes and they did not return.

After doing some reading on this site I though my symptoms best resembled a vac leak but could not find one. Then I thought a faulty fuel rail pressure sensor even though it didn’t give a code for it so I pulled the manifold and changed it. This did not help, the problem persisted. Next on my list was a good throttle body cleaning and fuel filter, did that but no change. Frustrated, I changed the MAF/IAT sensor with a remanufactured one from napa and still no change. Just the other day I seafoamed the truck (skipped adding any to the crank case) and the problem didn’t manifest itself for almost a whole day, I though that might have done it but the problem came back that night.
It still feels like a vacuum leak but I’m not having any success finding it.
Before I go for big ticket Items like throttle body, fuel pump, or coils/wires/plugs does anyone have any suggestions?

EGR Valve?

 

[BrooklynBay]

Do you have a time delay when you press the throttle pedal? It might be an issue with the throttle by wire system. There's a TSB for it which recommends flashing the PCM to install a new set of codes. Sometimes the actuator could bind.

 

[explorerphil]

I do have the typical laggy throttle response, mine is an 05 and that TSB is only applicable to vehicles built before October 4th 2004. I'll check my build date when I get home.

 

[lincolnshibuya]

I bet cleaning the egr valve will help.

 

[explorerphil]

so i cleaned out the egrand it looks good. a little gummy but the valve moves freely. t started it backup and had the same problem, she hesitates then stalls while at idle. new sympom though, if i pin the throttle it only revs up to 3450rpm and wont go any higher. my throttle position sensor reads at only 20.2 or 20.4% when i hold the throttle all the way down. all this while it is in park. any ideas what next? im not sure if this drive by wire mech does that normally, i doubt thats the case but i dont have anothe explorer to test it out on. lol.

 

[explorerphil]

Update

When I drive the explorer the engine can easily be brought up over 3500rpm. I will ask a more pointed question: While in park or neutral will the rpms be limited to 3500 rpm?

Maybe I'm just crazy but I didn't notice this in the past...

 

[swshawaii]

When I drive the explorer the engine can easily be brought up over 3500rpm. I will ask a more pointed question: While in park or neutral will the rpms be limited to 3500 rpm?

Maybe I'm just crazy but I didn't notice this in the past...

Neutral/Park Rev Limiter.
http://www.explorerforum.com/forums/showthread.php?t=233903&highlight=rev+limiter

 

[explorerphil]

Neutral/Park Rev Limiter.
http://www.explorerforum.com/forums/showthread.php?t=233903&highlight=rev+limiter

Ok, that makes sense. this is the first vehicle I've ever had that had a park/neutral limiter. Thanks for the in for swshawaii!

Any one got anymore opinions on my stalling issue? this problem is getting annoying

 

[MountyHall]

Try cleaning the throttle body with CRC Throttle Body Cleaner really well. I had to soak it really good. I cleaned the MAF and EGR first to no avail. Run some HEET through it as well. It did the trick for me.

 

[1996EB]

Try cleaning or replacing the IAC valve. Your initial stalling symptoms were very similar to mine and it was the IAC valve. I replaced mine about 2 years ago. It may have thrown a trouble, but I can't recall for sure. There have been a number of posts in the forum about this.

 

[lincolnshibuya]

2004-2005 are throttle by wire models, IAC is integrated into the throttle body.

 

[Joe in NY]

Interesting on the rev limiter. My 02 V8 is drive by cable and the rev limiter is around 5,500 rpm. Gets there fast too... Not that I do it often.

^^^^ also very true. Electronic throttle bodies allow for the delete of IAC solenoids. My explorer is the 2nd car I have seen with an IAC. The first was my friends 1986 BWM 325ES.

 

[explorerphil]

Try cleaning the throttle body with CRC Throttle Body Cleaner really well. I had to soak it really good. I cleaned the MAF and EGR first to no avail. Run some HEET through it as well. It did the trick for me.

The first thing I did a month ago was clean the throttle body. It is in minty* condition. That doesn't mean there is not an electronic problem with it but everything seems to be working with it.

 

[Bobmbx]

How old are your plug wires? I just changed mine (with 200k on them), and a whole bunch of issues were resolved. In addition, while troubleshooting these ghosts in the machine that I had, I discovered bare wires all over the place.

See here: http://www.explorerforum.com/forums/showthread.php?t=415084

 

[explorerphil]

How old are your plug wires? I just changed mine (with 200k on them), and a whole bunch of issues were resolved. In addition, while troubleshooting these ghosts in the machine that I had, I discovered bare wires all over the place.

See here: http://www.explorerforum.com/forums/showthread.php?t=415084

I have been looking for stripped or broken wires and have not found any yet (I'm always looking though). I have been debating on whether or not I should change the plugs and wires. The reason I have not yet is that I expect that if I had wire problems the stalling would happen weather the engine was hot or cold...

I'm reconsidering this now, maybe I should change them. The spark plugs have about 13000 miles on them... to me that's reason enough

 

[explorerphil]

Issue resolved.

I took my ex to a dealership they scanned it to find that the crank sensor was failing once the engine warmed up. It was odd to me that this could happen without generating an error code but sure enough once I replaced it the stalling issue disappeared.

Thanks for everyone's input. I hope someone finds this useful in the future.

 

[BrooklynBay]

Thanks for the update! Your thread is now marked solved.

 

[Number4]

I've been told that Fords are slow to throw codes. You can have multiple misfires and yet not display any.

For the rest of us, ask the dealer how they ended up discovering it exactly.
Try to get a real answer, service writer won't give you one.

 

[Saik]

I see the crank sensors are pretty cheap. Is this an easily replaceable part with basic tools?

 

[explorerphil]

I've been told that Fords are slow to throw codes. You can have multiple misfires and yet not display any.

For the rest of us, ask the dealer how they ended up discovering it exactly.
Try to get a real answer, service writer won't give you one.

Actually I did ask them. They said that they put it on the scanner and could see that the signal from the crank sensor seemed to "fliker" when the engine heated up. After a while the signal would simply stop or die. In response to this the ECU stops the ignition. So it was like the ECU though the engine was off.

Anyways, its been a week now and I can confidently say the issue was resolved by replacing the Crank sensor.