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1992 mustang revs high at start-up

  • Thread starter Thread starter fox182
  • Start date Start date Mar 14, 2010
F

fox182

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Feb 22, 2008
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Mar 14, 2010
#1
  • Mar 14, 2010
  • #1
hey guys i have an 87 coupe with a 92 5.0, when i start the car it shoots up to 3 grand for about 3 seconds and then drops back down to normal ive replaced the iac and checked for any other problems, cant find anything, anyone ever have this problem?
 

2000xp8

SN Certified Technician
Aug 8, 2003
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Mar 14, 2010
#2
  • Mar 14, 2010
  • #2
Did you check the tps voltage?
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
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Mar 14, 2010
#3
  • Mar 14, 2010
  • #3
Any codes?

If the IAC is disconnected and you try to start it cold, will it catch without you holding the pedal down?
 
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fox182

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Feb 22, 2008
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Mar 14, 2010
#4
  • Mar 14, 2010
  • #4
i did disconnect the iac and it starts normal and runs better disconnected even though i just replaced it and i did check the tps it did just rain pretty bad i dont know if something got wet or what, thanks guys
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
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Mar 14, 2010
#5
  • Mar 14, 2010
  • #5
If it starts cold without the IAC connected, either the idle adjustment is out of whack or look for a vac leak.
 
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fox182

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#6
  • Mar 14, 2010
  • #6
Ill check the vacuum lines Its weird that it runs fine without the iac
 

91StangGT5.0

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Oct 21, 2009
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#7
  • Mar 14, 2010
  • #7
HISSIN50 said:
If it starts cold without the IAC connected, either the idle adjustment is out of whack or look for a vac leak.
Click to expand...

Mine starts on a cold start with IAC disconnected pretty easily and does not hold above 1000rpms at starts up for a few seconds like it does with it on. It just starts up and drops down bogging it down to 500rpms and then goes back up to 800 or so and jumps around a hundred rpms or so at idle...
 
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