Rough idle and stalling when ac is on..?
Thread Starter
Member
Joined: May 2011
Posts: 45
Likes: 4
From: Denver, Co
Rough idle and stalling when ac is on..?
My truck has been idling rough at stop lights and some times It stalls, but I just realized it only does it when the ac is on. I have changed the spark plugs, air filter, fuel filter, and I've cleaned the maf sensor and it's still doing it. Has anyone else had this problem and what fixed it?
Senior Member
Joined: Dec 2009
Posts: 1,030
Likes: 17
From: Pittsburgh, PA
Sounds like a bad IAC valve (Idle Air Control). It is a motor attached to the throttle which kicks it up when an extra load is put on the engine( Air Conditioner, etc.) It is probably sticking.
5 Year Member
Joined: Sep 2010
Posts: 285
Likes: 83
From: Austin Texas
What engine do you have? The 5.4's do not have an IAC.
Have you tried reseting the idle?
From my ford book.
Reset the computer by removing a batery cable for 10 min.
1. Run the engine until it reaches normal operating temerature.
2. Allow the engine to idle for atleast 1 minute.
3. turn the a/c on and allow the engine to idle for atleast 1 minute.
4. drive the vehicle to complete the relearning process
Have you tried reseting the idle?
From my ford book.
Reset the computer by removing a batery cable for 10 min.
1. Run the engine until it reaches normal operating temerature.
2. Allow the engine to idle for atleast 1 minute.
3. turn the a/c on and allow the engine to idle for atleast 1 minute.
4. drive the vehicle to complete the relearning process
Senior Member
Joined: Jan 2010
Posts: 1,251
Likes: 21
From: Pittsburgh PA.
What engine do you have? The 5.4's do not have an IAC.
Have you tried reseting the idle?
From my ford book.
Reset the computer by removing a batery cable for 10 min.
1. Run the engine until it reaches normal operating temerature.
2. Allow the engine to idle for atleast 1 minute.
3. turn the a/c on and allow the engine to idle for atleast 1 minute.
4. drive the vehicle to complete the relearning process
Have you tried reseting the idle?
From my ford book.
Reset the computer by removing a batery cable for 10 min.
1. Run the engine until it reaches normal operating temerature.
2. Allow the engine to idle for atleast 1 minute.
3. turn the a/c on and allow the engine to idle for atleast 1 minute.
4. drive the vehicle to complete the relearning process
has anyone noticed any difference after resetting the idle using the above method?
Thread Starter
Member
Joined: May 2011
Posts: 45
Likes: 4
From: Denver, Co
Originally Posted by bjl95mustang
What engine do you have? The 5.4's do not have an IAC.
Have you tried reseting the idle?
From my ford book.
Reset the computer by removing a batery cable for 10 min.
1. Run the engine until it reaches normal operating temerature.
2. Allow the engine to idle for atleast 1 minute.
3. turn the a/c on and allow the engine to idle for atleast 1 minute.
4. drive the vehicle to complete the relearning process
Have you tried reseting the idle?
From my ford book.
Reset the computer by removing a batery cable for 10 min.
1. Run the engine until it reaches normal operating temerature.
2. Allow the engine to idle for atleast 1 minute.
3. turn the a/c on and allow the engine to idle for atleast 1 minute.
4. drive the vehicle to complete the relearning process
Junior Member
Joined: Dec 2009
Posts: 25
Likes: 0
I just fixed this on my truck...believe it or not I took the air intake off the throttle body and cleaned the throttle body out with fuel injector/carb cleaner and a soft rag. It was nasty in there....truck now idles perfect with or without the air on.
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Senior Member
Joined: Sep 2010
Posts: 227
Likes: 6
Yeah, did that, and still no difference, A little more throttle response, but other than that no help with the idle.
Senior Member
Joined: Jan 2010
Posts: 215
Likes: 0
From: Chantilly, VA
Not saying this is the cause of the issue..
Had an experience just like that with an old 95 Jetta where the AC wasn't great but it worked as long as I was driving, when I came to a stop it had a bad idle and would stall even with the clutch to the floor. Come to find out after stupid amounts of money spent at a shop diagnosing and replacing stuff that the condenser was bad. When I wasn't driving the little 2.slow motor didn't have enough *** to overcome the drag from the pulley.
Had an experience just like that with an old 95 Jetta where the AC wasn't great but it worked as long as I was driving, when I came to a stop it had a bad idle and would stall even with the clutch to the floor. Come to find out after stupid amounts of money spent at a shop diagnosing and replacing stuff that the condenser was bad. When I wasn't driving the little 2.slow motor didn't have enough *** to overcome the drag from the pulley.
