5.0L (1979-1995) Mustang Technical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.

Cold start surging idle

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Old 01-21-2012, 07:53 PM
  #1  
Project 5.GO!
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Default Cold start surging idle

When I start the car at night, the motor turns over and starts fast enough, but unless I give it gas after I start it, when the revs come down from the start, it will stall. For about 2-3 minutes after it starts, it will idle very low, on the verge of stalling, and I pretty much have to keep my foot feathering the gas to keep it from stalling as I pull out of a parking space or at a light. After it warms up, its fine.

When I start it in the daytime when the temperature is over 75, it will start and idle perfectly, every time. No stalls at all.

The IAC was my go-to fix for any idle problems, but after cleaning it, there was no change.
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Old 01-21-2012, 11:24 PM
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TrimDrip
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I would run codes and check for vacuum leaks.
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Old 01-22-2012, 01:07 PM
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mattdel
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Vacuum leaks would likely effect it no matter the temperature. I'd be looking into BAP problems, code 22.
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Old 01-22-2012, 05:36 PM
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Hmm, the BAP sounds like it might cause it to act differently at colder temps... I don't have any CEL going, but I'll try to run codes anyways.
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