• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

idel problems on a 1990 GT

  • Thread starter Thread starter fastback65chris
  • Start date Start date May 26, 2004

fastback65chris

New Member
Mar 26, 2002
46
0
0
Wichita Kansas
May 26, 2004
#1
  • May 26, 2004
  • #1
I have a 1990 GT and when the engine is hot and I have the a/c on the idel will run from 800 to 2000 rpm until the car amost dies can anyone help me on this. Also when the engine is hot the starter will drag when starting. I have already replaced the starter with a new one and still have the same issue I have also replaced the voltage regulator and the coil
 

SCORPION

New Member
Mar 2, 2004
386
0
0
Seaford, DE
May 26, 2004
#2
  • May 26, 2004
  • #2
I just fixed this problem on my 90 LX....

You have to make sure your TPS is getting the right amount of juice. I don't know the exact proceedure, but contact M8KMDAY (he did mine) and he will be able to walk you through the process.
 

fastback65chris

New Member
Mar 26, 2002
46
0
0
Wichita Kansas
May 26, 2004
#3
  • May 26, 2004
  • #3
was it a minor adjustment or did you have to replace something and does your stang run real hot at idel
 

fastback65chris

New Member
Mar 26, 2002
46
0
0
Wichita Kansas
Jun 8, 2004
#4
  • Jun 8, 2004
  • #4
I replaced my tps and this seemed to fix the idel issue with the cold start up but I also have another issue when you turn on the ac and the it kicks in it drops my idel down by 400 rpms and when the cluthc on the compressor disengages the idel comes back up to 800 do you know what part controls your idel when your compressor kicks on or what part idels your car up when your compressor turns on?
 

bmorrisj

Member
Sep 26, 2003
449
0
17
Buena Park, CA
Jun 8, 2004
#5
  • Jun 8, 2004
  • #5
its your iac....the eec is supposed to compensate with the engine load from the A/C.... disconnect the battery and let the eec relearn idle...
 
You must log in or register to reply here.

Similar threads

B
Electrical Why does my fox body keep frying eecs
  • brandyn200
  • Jun 20, 2026
  • Fox 5.0 Mustang Tech
Replies
8
Views
477
Fox 5.0 Mustang Tech Jun 25, 2026
AeroCoupe
P
Fuel New Eldebrock 1406 problems 1985 GT 5.0
  • Paddyman
  • Oct 22, 2026
  • Fox 5.0 Mustang Tech
Replies
4
Views
161
Fox 5.0 Mustang Tech Nov 2, 2026
manicmechanic007
M
85 mustang 5.0 cranking in run position
  • Mamaclean
  • May 23, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
3
Views
242
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 1, 2026
General karthief
F
Fox 1990 Mustang GT 5.0 A9L – Engine suddenly shuts off but immediately restarts when key turned
  • FishermansFriend
  • Aug 9, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
16
Views
656
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Aug 30, 2026
General karthief
B
Fuel 1990 mustang gt 5.0 no ground signal to fire injectors
  • brandyn200
  • Sep 5, 2025
  • Fox 5.0 Mustang Tech
Replies
6
Views
347
Fox 5.0 Mustang Tech Sep 6, 2025
Noobz347
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?