Engine stalls at idle, why?

Tiny
ALEXTTT
  • MEMBER
  • 2003 FORD EXPLORER
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
Car will stall at idle but will start right back up. It did this twice while at a stop light. No codes popping up.
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Wednesday, July 15th, 2020 AT 5:45 PM

37 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

This could be a few different things. First, an engine vacuum leak can cause a rough idle or even stalling. Also, an idle air control valve (IAC) is responsible for maintaining the engine's idle speed. That can be failing and not set a code.

When you turn the A/C on and off, do you hear the idle speed up to compensate for the added load of the compressor? Also, have you looked for any vacuum leaks? Here is a link that explains how it is done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

As far as the IAC, I need to know the correct engine size. The 5.4L was not an option on the Explorer. However, here are a couple links you may find of interest. One explains how to service the IAC and the other shows in general how one is replaced.

https://www.2carpros.com/articles/idle-air-control-valve-service

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

Let me know if this helps and the correct engine size so I can look further into the issue.

Take care,
Joe

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Wednesday, July 15th, 2020 AT 6:25 PM
Tiny
KASEKENNY1
  • EXPERT
You said this is an Explorer with a 5.4L. I assume you meant Expedition or did you get the engine wrong? I attached the info on the IAC for the 5.4L which is the most common cause of this.

I attached a guide on how to clean this but it is not that expensive so you may want to just replace it.

https://www.2carpros.com/articles/idle-air-control-valve-service

Let's run through this and let us know what happens. Thanks
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Wednesday, July 15th, 2020 AT 6:26 PM
Tiny
AL SWEARINGEN
  • MEMBER
  • 2003 FORD EXPLORER
  • 4.6L
  • V8
  • 4WD
  • AUTOMATIC
  • 130,564 MILES
I repaired a vacuum hose going to the throttle body! When I start the vehicle up, it idles fine! When I put it in gear, sometimes the rpm's drop real low and it wants to die! Sometimes it will die if I'm sitting at a light or the rpm's will jump up and down and eventually will die! There are no codes, so I wouldn't think it would be anything associated with a emission part! Any help would be deeply appreciated! Thank you!
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Friday, October 9th, 2020 AT 12:35 PM (Merged)
Tiny
CJ MEDEVAC
  • EXPERT
Taking a vacuum line loose (letting the intake suck in air) may have bypassed a "going bad" or "dirty IAC" (fix the issue, put the line back on.)

The "IAC" regulates air to idle the modern engine. Its a bypass over the "closed throttle plate" and the computer moves a plunger within it to regulate just the right amount of air flow thru it

This may not be the answer, but you can EZily rule it out! This will sorta guide you to what you have to do, it is really EZ to do!

My wifes' is on the top and has 2 bolts. Our Escape would idle low, then it got to point it would die when you stopped. Revving + holding brake was only way to keep it running.

Took it to fellow R/C airplane pilot, he doubles as a S.C. State HWY DEPT mechanic.(I still live in the carburetor age!).

When I got to his house, he was repairing a tractor. Told him my sob story. Escape was still barely running.

I raised the hood. He said, (and I quote)."It could be the IDLE AIR CONTROL (IAC)", as he pointed to it, and emphasized it with a sharp rap using the wrench in his hand.

It straightened right up, and ran darn good!

That was a 15/16 Craftsman wrench, box end, kinda a medium rap.

We removed and cleaned it, it may have gone on being Fine, for a lot longer.

Since it was my wife's, I took no chances, with my Well-Being.

YES, I visited parts store and replaced it, figgered it had 100,000 miles on it, and constantly was a moving part, replacement of this component, was just preventative maintenance in my eyes.

Hope this helps. Hope I am dead on! Cleaning would be FREE (can of throttle body cleaner), and at least Maybe eliminate this factor out of the equation. You can go on and replace it later, if you have the same feelings about it as I did. It is not really expensive. Yours will look very similar to ours

Please let me know how this goes.

The Medic
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Friday, October 9th, 2020 AT 12:35 PM (Merged)
Tiny
JOKERZ
  • MEMBER
  • 2003 FORD EXPLORER
  • 63,000 MILES
This vehicle had a dead battery. 12v 337cca.
I repalced the battery.
Vehicle would then start and die immetiatley.
I replaced the spark plugs thinking that they were fuel fowled.
Vehicle would still start and die instantly.
The rpms rev up to 1200rpm then it just shuts off like the PAYS system is kicking in.
I used the IDS scan tool and performed a check for codes. None present.
I used the IDS and performed a PATS key erase and reprogam of the factory keys.
It says I perfomred that correctly.
The vehicle still starts and dies.
Has this happened to anyone before after a battery repalcement?
Any help would be appriacted.
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Friday, October 9th, 2020 AT 12:35 PM (Merged)
Tiny
MHPAUTOS
  • EXPERT
Have you check for fuel pressure yet?
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Friday, October 9th, 2020 AT 12:35 PM (Merged)
Tiny
JOKERZ
  • MEMBER
Thanks for the reply.
I checked fuel pressure. 50-60 psi at key on and during motor run time.
I also have spark (checked with an inline spark checker)
I noticed that the red light on the center of the dash flashes
when I put the key in the ignition, but it does not flash while the vehicle starts and dies.
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Friday, October 9th, 2020 AT 12:35 PM (Merged)
Tiny
SEAHOLM
  • MEMBER
  • 2003 FORD EXPLORER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 87,000 MILES
Our vehicle starts fine, but when we put push the brakes in to go into drive the car shuts off. If the vehicle is put into neutral we can put it into drive (without applying brakes) and the car stays running. Why is it doing this? We heard it might have something to do with the vacuum assist.
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Friday, October 9th, 2020 AT 12:35 PM (Merged)
Tiny
JACK42
  • EXPERT
Very possible. Unhook the vacuum booster and plug all lines. Try it to see if it stalls again, if not the booster or check valve may be bad
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Friday, October 9th, 2020 AT 12:35 PM (Merged)
Tiny
13JAMES13
  • MEMBER
  • 2003 FORD EXPLORER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 45,000 MILES
When starting my Explorer, it starts up just fine and remains idling just fine. But when the engine is cold (hasn't been started in several hours) as soon as I shift it to reverse or drive the car begins to idle down to the point it will stall. I am able to keep it going just by giving it a little gas. Right after the intial stall it won't have any problems after that until the car has sat for about a 12 hour period of time. Its just that initial startup and shift into a gear. My thoughts are that it may be the fuel filter that is clogged up with some gunk. What are your thoughts?
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
TTRAN
  • MEMBER
James,
You have the same problem as mine years ago.
Have you tuned up your car recently?
I had my car tuned up around a year and the car started to have the same problem as yours.
You should try what I am going to tell you. It should work without any problem everytime you start and drive the car.
Open your air intake manifold to check if it is dirty. Mostly, my Explorer after 4 years, inside the intake manifold was so dirty. I cleaned it from the air filter all the way to the intake manifold with soap. The intake manifold I cleaned it with a bottle of injector throttle cleaning. I sprayed it once and wiped the dirt and oil off and again and again for half of a bottle. Wiped it out again and make it really clean. Then put the rubber duck together. Started the engine and hola. The problem had never came back again.
I am not a mechanic, but most of the job I have recently done with out driving to a dealer for more than 4 years now. Now, I am trying to replace the steering pump. I like the way this car handle, but it is a piece of junk. There are too many problems have gone wrong with it.
I just want to share with you.
Tony
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
DAVIS1231
  • MEMBER
  • 2003 FORD EXPLORER
  • 4.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 165,479 MILES
Isent my question already. But here it is again. My truck wont stay running after cranking up. I changed my plugs and wires, changed my mass air flow sensor. Getting a code reading of the following injector stuck open cylinder 1, tempature below temp, random miss fire 1, 3, 5 cyliders, to lean and to rich reading bank 1
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
PACO8224
  • EXPERT
That injector will cause a lot of problems. According to your codes you need to get that injector replaced before moving any futher.
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
BUTTONS1983
  • MEMBER
  • 2003 FORD EXPLORER
  • 166,000 MILES
My 2003 ford explorer recently has been dying on me at stop lights and or when slowing down. The check engine light only illuminates when this happens and when I restart the vehicle it is no longer on. We have taken it 2 places to have the codes pulled and there are none that come up. We have had our alternator, battery and starter tested but every time it dies the battery light comes on we are out of guesses. We have changed the oil, a fuse that was blown and the air filter just because our book listed these as possible problems. It doesn't die when the engine is cold it has to be driven for awhile like 20-30 min before this starts. Any suggestions would be much appreciated
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
WRENCHER1
  • MEMBER
Does the check engine light come on while the engine is still running or after it has stalled?
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
BUTTONS1983
  • MEMBER
The check engine light only comes on after it has died it is not on while the car is running
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
WRENCHER1
  • MEMBER
That's normal.

You may have a bad IAC ( idle air control) but try eliminating any vacuum leaks and cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
BUTTONS1983
  • MEMBER
Thanks for the advice I will try that
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
GEOFFREY
  • MEMBER
  • 2003 FORD EXPLORER
  • V8
  • 4WD
  • AUTOMATIC
  • 96,000 MILES
Engine stalls when cold at stops-V8. Once engine warms up idle low when stopping. Fuel filter changed 5 months ago at dealer?
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Friday, October 9th, 2020 AT 12:36 PM (Merged)
Tiny
WRENCHER1
  • MEMBER
You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.
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Friday, October 9th, 2020 AT 12:36 PM (Merged)

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