91 5.0 with erratic high idle

1993SSP

Founding Member

Sep 5, 2001

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Ky

Nov 26, 2008

#1

• Nov 26, 2008

• #1

Got the car out for a drive today and cleaned it up. The idle is fine when it's first started, but during driving it wants to idle at 2K rpm, I have checked all my connections. What could be the culprit?

 

Black1987Stang

Active Member

Aug 22, 2004

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Jersey Shore

Nov 26, 2008

#2

• Nov 26, 2008

• #2

I vote for dirty/sticking idle air control valve aka iac but a few other examples could be...

vacuum leak
sticking throttle body or linkage...if the throttle plate is resting against the stop when its doing it then this isn't the prob.

I would unplug the iac when its doing it and see what it does then go from there...

 

1993SSP

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Sep 5, 2001

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Nov 26, 2008

#3

• Nov 26, 2008

• #3

the IAC was my first suspect, I'll check into it further when I have more time tommorrow, whenever it does it I can turn off the engine while driving and re start and the idle goes back to around 900rpm, just annoying as hell

 

Black1987Stang

Active Member

Aug 22, 2004

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Jersey Shore

Nov 26, 2008

#4

• Nov 26, 2008

• #4

I also heard a bad tps can do what you just described....check the output voltage of it at idle when it's doing it.....but my first bet would be the iac...

 

1993SSP

Founding Member

Sep 5, 2001

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Nov 26, 2008

#5

• Nov 26, 2008

• #5

The voltage should be .095 right?? I pulled the IAC, It has been modded so that the valve is bypassed, the metal in the middle has been ground down. I'll prob go with the TPS, the idle would sometimes go back down when I would also tap the gas while in neutral.

 

dcurtis

10 Year Member

Jan 19, 2006

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Nov 26, 2008

#6

• Nov 26, 2008

• #6

I just recently had the same exact problem, not with the stang but, I thought it was the IAC but if I unplugged the tps my car would idle fine, plug it back in and the idle would climb to about 1900rpm's.

 

1993SSP

Founding Member

Sep 5, 2001

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Nov 26, 2008

#7

• Nov 26, 2008

• #7

Looks like a new TPS for me, should I go OEM or pick one up from a parts store?

 

asecretfile

New Member

Feb 11, 2007

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Nov 26, 2008

#8

• Nov 26, 2008

• #8

1993SSP said:

Got the car out for a drive today and cleaned it up. The idle is fine when it's first started, but during driving it wants to idle at 2K rpm, I have checked all my connections. What could be the culprit?

Click to expand...

If it does ok at first startup but acts up afterwards might be your ECT sensor

 

FrankenStang

Now, give me a damn CT!

15 Year Member

Apr 16, 2005

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Florence, Az

Nov 26, 2008

#9

• Nov 26, 2008

• #9

Hmmm, my Capri is doing the same thing.

*takes notes*

 

Mr. Rustypwnz

Advanced Member

Jun 1, 2005

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indianapolis/ valdosta ga

Nov 27, 2008

#10

• Nov 27, 2008

• #10

sounds like its idling too high and erradic?

 

1993SSP

Founding Member

Sep 5, 2001

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Nov 27, 2008

#11

• Nov 27, 2008

• #11

The ECT, mounted in the coolant tubes that run to the heater core correct??

 

D

dr59l

New Member

Nov 24, 2008

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Nov 27, 2008

#12

• Nov 27, 2008

• #12

go to ford and get a tps, parts store electronics are junk! i put three of them on my lightning till i broke down and bought a oem one. fixed it immediately

 

asecretfile

New Member

Feb 11, 2007

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Nov 27, 2008

#13

• Nov 27, 2008

• #13

1993SSP said:

The ECT, mounted in the coolant tubes that run to the heater core correct??

Click to expand...

yea