High Idle Problem (SES on) HELP!

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ngjcs3

New Member

Jun 11, 2003

71

0

0

philly suburbs / state college, PA

Jun 11, 2010

#1

• Jun 11, 2010

• #1

My car is idling very high around 1500 RPM. Sometimes the idle would come down to normal to ~800 or so but only when I am completely stopped. When I am driving the car feels like it's on cruise control. The engine wants to stay at ~1800 RPM if I am just cruising in any gear. How do I trouble shoot this? Any help is appreciated! Thank you!

 

N8Dogg98

15 Year Member

Apr 4, 2005

3,872

238

184

MN

Jun 11, 2010

#2

• Jun 11, 2010

• #2

Likely culprit is the IAC valve. Best bet is to buy a new one and replace it.

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Jun 11, 2010

#3

• Jun 11, 2010

• #3

How to troubleshoot IAC idle problems

Check out post #3:

http://www.stangnet.com/mustang-forums/810729-starts-but-dies-idle-help.html

Look esp for vacuum leaks or TB linkage binding.

Did you alter the TB set screw? If the set screw is allowing too much air to enter, the idle will be too high. Remember that the IAC can only ADD air (not remove it).

In the end, most ppl find that replacing the IAC solves their problem.

 

N

ngjcs3

New Member

Jun 11, 2003

71

0

0

philly suburbs / state college, PA

Jun 11, 2010

#4

• Jun 11, 2010

• #4

Thanks for all the helpful input.. I will try replacing the IAC. But is there a way that I can sure that IAC is the problem? I don't want to buy one which will be a waste. And no I have not touched the TB screw..

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

204

Houston Texas

Jun 11, 2010

#5

• Jun 11, 2010

• #5

Did you read the post? There is information on how to do a basic functionality test of the IAC.

Do you have an ODB2 scanner? There was also ways to cross check the IAC duty cycle vs what the car is actually doing.