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Idle hangs when coming to a stop

  • Thread starter Thread starter 50 Proof
  • Start date Start date Feb 4, 2011
5

50 Proof

Member
Jul 14, 2003
43
1
9
Orange County
Feb 4, 2011
#1
  • Feb 4, 2011
  • #1
I have an 01 Bullitt with 97k miles. As I'm coming to a stop, sometimes my idle will hang and the engine will sound a lot louder. Is this a symptom of a bad IAC?
 

patman0911

Founding Member
Jun 5, 2002
2,287
0
46
Tuscaloosa, AL
Feb 4, 2011
#2
  • Feb 4, 2011
  • #2
How high are they hanging? A couple hundred RPMs above idle is normal and they should drop after a few seconds at rest. If, once it's warmed up, it's hanging at, like, 1500 RPM then something is wrong.
 
5

50 Proof

Member
Jul 14, 2003
43
1
9
Orange County
Feb 4, 2011
#3
  • Feb 4, 2011
  • #3
It'll hang around 2k rpm, give or take a couple hundred rpm. My 94 gt did something similar where the idle was constantly stuck at 2500-3000 rpm and turned out to be a bad idle air control valve. That's why I suspect bad iac on my Bullitt but I don't know what else could cause this.

It doesn't do this all the time, its random and infrequent
 

twogts4us

15 Year Member
Apr 1, 2004
4,188
12
79
Dunedin, FL
Feb 5, 2011
#4
  • Feb 5, 2011
  • #4
You hit it - it's the IAC. You can clean it and buy some time, but sooner or later you'll want to replace it.
 
N

needparts

New Member
Sep 6, 2010
2
0
0
Feb 5, 2011
#5
  • Feb 5, 2011
  • #5
twogts4us said:
You hit it - it's the IAC. You can clean it and buy some time, but sooner or later you'll want to replace it.
Click to expand...

I agree and disagree with this comment. I clean mine and it did buy me some time. Like 4yrs. I have 172K miles and it's still going strong. However I'm gonna be replacing it soon.
 

Steve491

Member
Apr 20, 2008
254
2
19
Charlotte, NC
Feb 6, 2011
#6
  • Feb 6, 2011
  • #6
Check the vacuum lines, especially the big ones like the PCV coming out of the intake. They might look good, but they get loose and leak air depending on the temperature.
 

twogts4us

15 Year Member
Apr 1, 2004
4,188
12
79
Dunedin, FL
Feb 6, 2011
#7
  • Feb 6, 2011
  • #7
needparts said:
I agree and disagree with this comment. I clean mine and it did buy me some time. Like 4yrs. I have 172K miles and it's still going strong. However I'm gonna be replacing it soon.
Click to expand...

Impressive!
 

Rejekt

Member
Aug 12, 2010
546
13
18
Raleigh, NC
Feb 6, 2011
#8
  • Feb 6, 2011
  • #8
needparts said:
I agree and disagree with this comment. I clean mine and it did buy me some time. Like 4yrs. I have 172K miles and it's still going strong. However I'm gonna be replacing it soon.
Click to expand...

Yep, I cleaned mine 2 years ago and have had no trouble since lol
 
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