Engine stalls at idle, What is wrong?

Tiny
RJONES
  • MEMBER
  • 1999 FORD F-150
  • 19,500 MILES
1999 Ford F150, 4.6L, 195,000 miles. The engine goes to a slow idle and then dies. At idle the heater fan slow down, like loss of power?
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Wednesday, February 15th, 2012 AT 7:22 PM

66 Replies

Tiny
FIXITMR
  • EXPERT
Check ICV valve. same as IAC. are you saying idle slows fan or fan slows idle? extra draw from alterantor does put a slightly higher load on engine. if it's too lean already this could slow down idle. idle slowing down lowers output from alternator so fan itself gets less voltage and slows down.

This guide can help us fix it

https://www.2carpros.com/articles/stall-at-idle

Please run down this guide and report back.
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Wednesday, February 15th, 2012 AT 7:44 PM
Tiny
GSROOSE11
  • MEMBER
  • 1999 FORD F-150
  • 4.2L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 247,000 MILES
I tried to start it and got a backfire from under the hood, but it did not start. I turned the key again and it started, but it revs to 3000 rpm's, and then tries to drop to stall unless I work the gas peddle. It gives of a thin white smoke from the rear of the engine when I force it to stay running for a minute, and whistles from what sounds like somewhere in the front or passenger side of the engine.
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Monday, August 24th, 2020 AT 9:55 AM (Merged)
Tiny
HMAC300
  • EXPERT
Try cleaning throttle plate on both sides and IAC hole with choke cleaner then check for a vacuum leak like hose off broken etc. Finally scan for codes.
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Monday, August 24th, 2020 AT 9:55 AM (Merged)
Tiny
RENEE
  • ADMIN
Hi GSROOSE11,

If you decide you would like to conduct the scan yourself here is a link to an article that features written step by step instructions and pictures explaining how to do the scan yourself, also I have included a link to our YouTube channel with a how to video on code scanning.

This is applicable even if your check engine light is not on.

Most scanners are inexpensive to purchase, you can purchase one online from sites like Amazon.com

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

https://youtu.be/YV3TRZwer8k

Once you have the codes please get back to us so that we can further assist you. We are always happy to help.

Thank you for visiting 2CarPros.com.

Kindest regards,

Renee
Admin
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Monday, August 24th, 2020 AT 9:55 AM (Merged)
Tiny
B00SH00
  • MEMBER
  • 1998 FORD F-150
  • 6 CYL
  • 2WD
  • MANUAL
  • 125,000 MILES
During idle speed engine is very prone to stall out when conditions are damp (snow rain).
-after stalling out, engine does not start back up immediately. Usually requires a wait of 1-5 minutes and several attempts at cranking it over.
When attempting to crank over I do provide a little pressure on accelerator; this helps, but again, I usually must wait a brief time period before engine starts back up.

Vehicle recently acquired and history of tune ups are missing. However I did replace plugs and they were very deteriorated.

Thanks!
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
2CEXPT
  • EXPERT
Do you have a check engine light On or has flashed if so get the computer scanned for code/s.

You need to replace the rest of the tune-up parts such as distributor cap and rotor/fuel filter/wires etc.

Also have the engine coolant temperature sensor/throttle position sensor and the idle speed control motor/valve checked out.
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
B00SH00
  • MEMBER
The Check engine is not on.

I replaced the wires fuel filter etc.

I replaced the TPS sensor and idle speed control/.

Truck still stalls out when damp and cold.

Any more ideas would be very helpful.

Thank you.
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
SANMAR
  • MEMBER
  • 1998 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 50,000 MILES
Engine starts, but it will not stay on. If I give it some gas it will run, but if let it go, it will stall. Truck does not idle.

It happened before, but after a few tries, it started and did not have problems through that day. Today is cold and it will not stay on after a lot of tries.

What could be the problem?

Mario
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
FLEXY5
  • MEMBER
Sounds like it needs an IAC valve. You can try to clean it, but I haven't had much success with that being a long term solution. It will eventually need to be replaced.
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
BLACKOP555
  • EXPERT
I have to agree with dave on this one but I have one more question.

Does it idle fine when the engine has warmed up?
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
SANMAR
  • MEMBER
Don't know. When it happened before and it started, after a few tries, it ran good. I did not notice anything different.
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
RAM493
  • MEMBER
  • 1997 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 430,000 MILES
I am trying to trace a problem with this truck. It will start and idle up by the IAC and come back down and shut off. It does this every time you start it. If I try to press the accelerator to keep it running and it will idle extremely rough for a period, clear out and rev up but wont idle if I let up on the pedal. Is this a MAP OR MAS sensor problem and how do I test to see? I am limited on current info and tooling for late model cars and trucks and am trying to diagnose the best I can with current knowledge and equipment. Any help would be greatly appreciated. If you feel it could be anything else let me know what to check for. It also has no trouble codes.
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
2CEXPT
  • EXPERT
Try cleaning out the IACV and also the EGR and PCV valves
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
RAM493
  • MEMBER
Is there any other feedback on this problem. All info will be appreciated. Especially testing of the MAP and MAS sensors. Thanks.
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
JON PHILLIPS
  • MEMBER
  • 1997 FORD F-150
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 251,936 MILES
My 1997 ford v6 4.2 wont idle. It will start and drive but I have to keep pumping the gas pedal to keep it from dying
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
CJ MEDEVAC
  • EXPERT
OK, Keep in mind, I'm trying to help!

Wife's '03 Escape had same issue

You might clean this, or replace it as I did (I figured 100,000 miles was plenty for this thing to have done it's job!)

Talking about the IAC

Yours is probably close to this location----may differ slightly in looks.

This controls the combustion air needed for idle. Kinda Bypasses the throttle plate.

The Parts store can point it out!

Here's the pics I took of hers

Let me know how it's going

The Medic
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-1
Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
OBXAUTOMEDIC
  • EXPERT
Hello,

To add on to CJ MEDEVAC.

Check for vacuum leaks, also is engine light on if so getting codes read will help in finding problem.

One thing to try with the IAC (Idle Air Control) Valve, Disconnect the electrical connection. Doing this will cause the computer to enter into a default mode and engine should run properly if it is the cause.
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Monday, August 24th, 2020 AT 9:56 AM (Merged)
Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 1997 FORD F-150
  • 209,600 MILES
I can get my truck to start, barely.
It wont idle
If I keeep the rpms up around 4000 it smoothes out
Then it just quits
Pumping the daylights out of it SOMETIMES will get it to recover
I can here the fuel pump working when I turn the ignition on
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Monday, August 24th, 2020 AT 9:57 AM (Merged)
Tiny
MA AV
  • EXPERT
When did this start, around the same time as something else? Start by checking your air intake tube, from the air filter up to the throttle body checking for any disconnected hoses or cracks or missing clamps. Then I would check the left and right side valve covers pcv hoses, there are one on each side and route to under the throttle body. Report back
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Monday, August 24th, 2020 AT 9:57 AM (Merged)
Tiny
ECMC
  • MEMBER
  • 1996 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 82,000 MILES
1996 F-150 stalled a few times now will not stay running seems worse in cold weather or rain
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Monday, August 24th, 2020 AT 10:00 AM (Merged)

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