Low idle

Tiny
THEBOZ
  • MEMBER
  • 2007 FORD MUSTANG
  • 16,000 MILES
I have a 2007 Mustang GT that had a problem with surging followed by a low idle. After I replaced the battery it refuses to idle at all. Anybody know what would cause this?
Thursday, December 20th, 2012 AT 6:07 PM

23 Replies

Tiny
DRCRANKNWRENCH
  • MECHANIC
  • 3,380 POSTS
It sounds like you have 2 problems going on here. First the Idle Air Control Valve , IACV, has failed or needs cleaning. It is located on the intake manifold near the throttle body. Second, when you install a new battery sometimes it takes a little coercing to get things to isle correctly. This walk through will explain. Just folow link below to get to it;

https://www.2carpros.com/articles/engine-stalls-idles-too-high-low-after-dead-or-replaced-battery

If you decide to clean the IACV then make sure to use brake cleaner and spray inwards towards the intake tract and clean the ports on the intake manifold as wel in the same fashion. This keeps deposits from being pushed closer to the IACV.
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Thursday, December 20th, 2012 AT 6:22 PM
Tiny
HILDALGO
  • MEMBER
  • 1 POST
  • 2006 FORD MUSTANG
  • V8
  • 2WD
  • MANUAL
  • 26,662 MILES
I have an 06 Gt Mustang and every time the air is turned on the car idles low and speeds back up. Also when coming to a stop the car almost stalls out but then picks back up. Of course ford says thats normal, but I know better any suggestions or tips?
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
DIEHARDAZM
  • MEMBER
  • 7 POSTS
Well, that's not normal because mine doesn't do anything at all when i turn the air on or come to a stop. sounds like the TPS throttle position sensor might be slow reacting and may need to be changed out. should be under warranty. if one dealership is un-willing to fix it. go to another dealership.

This guide can help fix it

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

Please run down this guide and report back.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
SHEILA KETTERMAN
  • MEMBER
  • 2 POSTS
  • 2006 FORD MUSTANG
  • 4.0L
  • RWD
  • AUTOMATIC
  • 106,253 MILES
Recently had it worked on and after he put it back together the idle is low and seems to bounce and pulse. It now has a flutter sound. It did not do this before he took it apart.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Take it back to him so he can see if he left something disconnected he should fix it for free depending on what was done.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
SHEILA KETTERMAN
  • MEMBER
  • 2 POSTS
I did, he said it was the mass airflow system and I should get rid of it. Thank you. I will just take it to the dealership.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Sounds like the guy does not know to much or what to do he is probably talking about mass air flow sensor. Make sure ductwork going from engine to air cleaner is on correctly and has no holes in it.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
PHILLIPS49
  • MEMBER
  • 2 POSTS
  • 2005 FORD MUSTANG
  • V8
  • 2WD
  • AUTOMATIC
  • 55,000 MILES
The car is a 2005 Mustang GT, 4.6L 3V automatic. The car is factory stock no mods.
I had to change the battery, The old battery was developing a shorted cell. After changing the battery over 3 weeks ago, I now have a problem with surging idle. It hunts up and down between 400 and 750 RPMS. It is amplified with the AC on. It sets a DTC p0506 "Idle RPM lower than expected" I can't find any vacuum leaks or air leaks. I followed a learn procedure, but mine must be really dumb. It hasn't learned anything yet. The air filter is stock and new. I replaced the TPS. No difference. There is no idle air control valve.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
The IAC is now called the electronic throttle control motor, and you do have one...on the throttle body!


https://www.2carpros.com/forum/automotive_pictures/62217_Mustang_1.jpg

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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
BARKLEE
  • MEMBER
  • 1 POST
I had the same problem I also have auto. FIRST remove the positive red battery terminal to start work. I removed entire CAI also TB, cleaned everything with carb/tb cleaner that you can get at ford also known as tune up cleaner. 2 sensors replaced throttle position sensor on the left of TB and the MAF. If you can't afford use electronic cleaner or non residue cleaner or MAF sensor cleaner and clean all sensors. Also spray the connectors with electronic cleaner. The TB had black gunk behind the butterflies. Also if the air cleaner is old replace or clean. I had the steeda cone filter. I cleaned it with k&n filter cleaner. I let it sit overnight everything to dry. The next day I did not over spray the filter with the special oil provide by k&n. I but the whole system back making sure all bolts tight and no air leaks out. FINALLY, return battery terminal back. With my diablosport tuner returned the original tune back to car waited a few minutes then returned the steeda/performane tune back to my mustang. Cycled the key then started. WOW
the car runs like brand new no idle surges no low idle p0506 no intermitant mass air volume blah blah
p0104. No check engine light the car is faster. Do this if you don't have any other problems with your car and the only codes are the above mentioned. After a few years the system gets dirty needs cleaning don't let dealer tell you that you need custom tune don't trust them to clean the system do it yourself, you only know how good is.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
May be a cleaning, but if you remove battery terminals to protect against accidental grounding, it's the (-) negative you remove.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
PHILLIPS49
  • MEMBER
  • 2 POSTS
Been meaning to get back to you guys with a responce. At first, I didn't think the information would be useful. After cleaning the MAF and replacing the the TPS I still had idle problems. I also had a throttle lag. Push the pedal gently. Nothing. Then all of a sudden the RPMS would jump up. It was also nearly impossible to hold a set RPM in neutral.
After reading the mechanics reponse, I bit the bullet and purchased a replacement throttle body which comes complete with the TPS and Throttle motor from Ford Discount Parts. It is now running as good as new. I think the throttle motor may have been bad. Thank you all! It is once again a pleasure to drive it.

Don
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
This guide will help fix it was well

https://www.2carpros.com/articles/throttle-actuator-service
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
  • 2001 FORD MUSTANG
  • 41,000 MILES
I have a problem with my Mustang, it will not idle without me pumping the gas?
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Is the check engine light coming on at all?
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
I will be general since you provided no motor size.

Idle control motor is a common failure.

Is the check engine light on?

Roy
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
YEHE
  • MEMBER
  • 2 POSTS
  • 2000 FORD MUSTANG
  • 158 MILES
I have a 2000 ford mustang. When I push the clutch in to shift the RMPs don't drop to an idle impeding me of shifting without a grinding noise. I have to wait til my car's RMPs drop below 2000 to shift the the next gear. I don't know what is doing this, I just started when I turned off my car and turned it back on after 5 minutes. The car idles and revs just fine with the clutch in and in neutral.
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Sound like the clutch is slipping preventing from you to shifting to the next gear
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
YEHE
  • MEMBER
  • 2 POSTS
Does that mean the clutch is going out?
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Friday, June 12th, 2020 AT 11:56 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Could be have it further checked
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Friday, June 12th, 2020 AT 11:56 AM (Merged)

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