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1991 Gt Foxbody Rough Idle/stalls

  • Thread starter Thread starter ddrew01
  • Start date Start date Nov 26, 2016
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    1991 fox rough idle
D

ddrew01

New Member
Nov 26, 2016
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Nov 26, 2016
#1
  • Nov 26, 2016
  • #1
So my 91 GT has been having some idling issues lately. Whenever I start the car it either stalls straight away if I dont step on the gas right away, or the RPMs will just jump around and it will not stay steady, and the eventually stall out. This past summer I took it on a pretty far road trip ( From NY to VA and back ) and ever since then this problem has been happening. I have tried just about everything you can think of. I replaced the IAC, adjusted the TPS, cleaned the MAF, I even tried flushing the the fuel system and nothing works at all. Also when the car is idling the battery level meter in the car goes up and down as well... Maybe that is the problem? I really want to get this fixed ASAP so any help would be greatly appreciated.
 

mikestang63

SN Certified Technician
Aug 27, 2012
11,606
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In the garage
Nov 26, 2016
#2
  • Nov 26, 2016
  • #2
run the codes
 

RaggedGT

Been here over a DECADE and still no CT
Mod Dude
Jul 20, 2014
4,739
3,188
203
Taylorsville ky
Nov 26, 2016
#3
  • Nov 26, 2016
  • #3
ddrew01 said:
So my 91 GT has been having some idling issues lately. Whenever I start the car it either stalls straight away if I dont step on the gas right away, or the RPMs will just jump around and it will not stay steady, and the eventually stall out. This past summer I took it on a pretty far road trip ( From NY to VA and back ) and ever since then this problem has been happening. I have tried just about everything you can think of. I replaced the IAC, adjusted the TPS, cleaned the MAF, I even tried flushing the the fuel system and nothing works at all. Also when the car is idling the battery level meter in the car goes up and down as well... Maybe that is the problem? I really want to get this fixed ASAP so any help would be greatly appreciated.
Click to expand...

Here is a thread,with a TON of info in it.. Somewhat overwhelming-but all very useful and will help you with your problem...
Step 1.- Pull Codes
Step 2.-Go through this check list

http://www.stangnet.com/mustang-forums/threads/help-me-create-the-surging-idle-checklist.698148/
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
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polk county florida
Nov 26, 2016
#4
  • Nov 26, 2016
  • #4
Run the codes, do the check list, I would look for a vacuum leak, and the alt. gauge will fluctuate with rps
 
D

ddrew01

New Member
Nov 26, 2016
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1
Nov 28, 2016
#5
  • Nov 28, 2016
  • #5
I also just installed a powered subwoofer. Could it be that the alternator is not powerful enough?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,260
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Massachusetts
Nov 28, 2016
#6
  • Nov 28, 2016
  • #6
ddrew01 said:
I also just installed a powered subwoofer. Could it be that the alternator is not powerful enough?
Click to expand...


Doubtful. You can find out by just turning the radio off.


Step #1, run the codes and post them here.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,929
10,573
203
polk county florida
Nov 28, 2016
#7
  • Nov 28, 2016
  • #7
karthief said:
Run the codes, do the check list, I would look for a vacuum leak, and the alt. gauge will fluctuate with rps
Click to expand...
rps? maybe rpms,
neeed. Moorre. Cofffffeee.
 
S

sawdeanz

New Member
Sep 6, 2016
13
0
1
Nov 29, 2016
#8
  • Nov 29, 2016
  • #8
I would listen to the smart people and follow the list but I would also mention the ignition system. I had similar issues that steadily grew worse and worse, with misfires and eventually an engine that would stall when I pressed the gas. Replacing the distributor solved the problem.
 
S

stpete

Well-Known Member
Dec 26, 2015
320
151
63
Nov 29, 2016
#9
  • Nov 29, 2016
  • #9
If you have underdrive pulleys, the stock alternator at idle doesn't put much out. Electric fans and high power stereo will cause problems.
 
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