Fox 88 Gt will not idle

Leeroy05 · Feb 1, 2025

I was recently experiencing an issue where whenever I would come to a sudden stop or a sharp turn at slow speeds my car would stall. It eventually got to a point where the engine would not idle at all. If i let off the gas, the car would die. I changed out the idle air valve and that fixed my issue completely for about a month. Today it started up again, the car will not idle at all. Could the IAC have gone bad again?

LILCBRA · Feb 1, 2025

Welcome to the zoo Leeroy05!

I suppose it's possible that it's gone bad.... it kinda sounded like a fuel issue for some reason - like the pump was being starved when fuel is being sloshed around. It's weird that swapping the IAC would've improved it the first time though. I'll let someone else chime in with their ideas, maybe they know something I don't.

Where in Iowa are you at? I'm from good old Waterhole....

Leeroy05 · Feb 1, 2025

LILCBRA said:
Welcome to the zoo Leeroy05!

I suppose it's possible that it's gone bad.... it kinda sounded like a fuel issue for some reason - like the pump was being starved when fuel is being sloshed around. It's weird that swapping the IAC would've improved it the first time though. I'll let someone else chime in with their ideas, maybe they know something I don't.

Where in Iowa are you at? I'm from good old Waterhole....

Yeah i thought so too at first, but after having read up a little i figured i would try the IAC, and to my surprise it fixed it.

And I am from des moines, visiting some family in waterloo at the moment though!

LILCBRA · Feb 1, 2025

Leeroy05 said:
Yeah i thought so too at first, but after having read up a little i figured i would try the IAC, and to my surprise it fixed it.

And I am from des moines, visiting some family in waterloo at the moment though!

Say hi to everyone for me!

I'll admit, you've kinda got me stumped atm. I'll let someone smarter than I am try to help more than I probably can. But one more thing that I can think of - how about the TPS? And I'm sure it'll help others with their diagnosis - what all is done to the car? Have you pulled any codes? That should hopefully help whomever jumps in.

Leeroy05 · Feb 1, 2025

LILCBRA said:
Say hi to everyone for me!

I'll admit, you've kinda got me stumped atm. I'll let someone smarter than I am try to help more than I probably can. But one more thing that I can think of - how about the TPS? And I'm sure it'll help others with their diagnosis - what all is done to the car? Have you pulled any codes? That should hopefully help whomever jumps in.

I have not checked tps, or pulled codes but that is something ive thought might be the issue also?

General karthief · Feb 1, 2025

Check fuel pressure too

AeroCoupe · Feb 2, 2025

First things you need to do is pull codes and check the fuel pressure. This is a great thread on just about everything that can affect the idle:

Thread 'Help me create the "Surging Idle Checklist"'

Apr 10, 2005

Updated 05 July 2022 to add rough idle when cold and smooth idle when up to normal operating temperature. See the EGR tech information, section #15 for more help.

Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank Checklist. They are very effective in finding and eliminating the problems by use of a systematic process that checks and eliminates possible causes. This idle problem checklist will use the same troubleshooting strategy and methodology.

By the term surging idle, I mean an idle that...

These cars are up there in age now and they do have an issue with the baffle breaking loose in the tank but that may only affect you with 1/2 a tank of less. Another thing is the hose between the fuel pump outlet and the fuel pump hanger. These can rot and develop leaks.

Fox 88 Gt will not idle

Leeroy05

Member

LILCBRA

I wish I didn't have all of these balls in the air

Leeroy05

Member

LILCBRA

I wish I didn't have all of these balls in the air

Leeroy05

Member

General karthief

wonder how much it would cost to ship you a pair

AeroCoupe

lube between the nut and the face. I know my lubes

Thread 'Help me create the "Surging Idle Checklist"'

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Fox 88 Gt will not idle

Member

I wish I didn't have all of these balls in the air

Member

I wish I didn't have all of these balls in the air

Member

wonder how much it would cost to ship you a pair

lube between the nut and the face. I know my lubes

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