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

1994 Mustang GT 5.0HO - Idle issue - Seeking advice

  • Thread starter Thread starter Mrlilwheeler
  • Start date Start date Jul 13, 2018
M

Mrlilwheeler

New Member
Oct 30, 2017
12
0
1
Jul 13, 2018
#1
  • Jul 13, 2018
  • #1
Posting here today to hopefully figure out dafuq is going on with my mustang. 94' 5.0HO.

List of new parts & adjustments.
- Plugs (.054)
- Coil
- Distributor (Adjusted timing to correct degree.)
- Wires
- Radiator & hoses
- Thermostat & Gasket
- Fuel Filter
- Bypassed Smog Pump

Car runs great 90% of the time. Sometimes, when coming to a stop, the idle will lower and raise like it's stumbling. If the motor gets stressed at all, it'll stall itself, or be close to it. The only thing I have left to replace is the fuel sending unit. (bad o ring.) Any help at all would be greatly appreciated.

1994 Mustang GT
5.0HO
T5
Stock headers, offroad x pipe, with two flowmasters that are dumped.
BBK CAI
Can't think of everything off the bat. Thank you for the help though.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,949
10,588
203
polk county florida
Jul 13, 2018
#2
  • Jul 13, 2018
  • #2
Check fuel pressure, check for codes.
For idle/stall help our resident tool (jrichker) here has developed (he may have had help from others, not sure) a surging idle checklist, it can be found here:
http://forums.stangnet.com/showthread.php?t=698148
Read it through then roll up your sleeves and start at the top and work your way through, don't skip around, it will help you find and fix things without wasting time and money.
In the tech forum you will find a technical/how to section that has lots of stuff of interest for swapping and modifying our cars.
Welcome to stangnet.
 

mikestang63

SN Certified Technician
Aug 27, 2012
11,606
8,859
214
In the garage
Jul 13, 2018
#3
  • Jul 13, 2018
  • #3
clean your IAC
 

FastDriver

I was uncomfortably high & wearing a helmet
SN Certified Technician
Sep 5, 2001
6,104
2,714
224
Vass, NC
Jul 13, 2018
#4
  • Jul 13, 2018
  • #4
Report codes first.

First thought: Bad idle air control valve?
 
M

Mrlilwheeler

New Member
Oct 30, 2017
12
0
1
Jul 14, 2018
#5
  • Jul 14, 2018
  • #5
0 Codes come back, but the TPS & IAC both look fairly weathered. Will report results soon.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,949
10,588
203
polk county florida
Jul 14, 2018
#6
  • Jul 14, 2018
  • #6
You got a code 11 (shows computer is communicating)?
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Jul 17, 2018
#7
  • Jul 17, 2018
  • #7
You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 250,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
 
You must log in or register to reply here.

Similar threads

Engine 1994 5.0 refuses to idle
  • FordFanatic1894
  • Jul 20, 2025
  • 1994 - 1995 Specific Tech
Replies
14
Views
556
1994 - 1995 Specific Tech Jul 22, 2025
General karthief
S
Fuel ‘88 GT Runs Rich Cold — Fixes Itself When I Unplug Sensors (ECT, MAF, O2, etc.)
  • Sufarry
  • Nov 6, 2025
  • Fox 5.0 Mustang Tech
Replies
12
Views
882
Fox 5.0 Mustang Tech Nov 9, 2025
Mustang5L5
C
1967 Mustang 5.0 swapped shuddering/sputtering issues
  • Cro67
  • Sep 24, 2025
  • Fox Engine Swaparoo
Replies
3
Views
245
Fox Engine Swaparoo Sep 25, 2025
General karthief
K
Engine 2000 Mustang GT - Fuel issue post-blown spark plug repair
  • kenster1092
  • Feb 26, 2026
  • SN95 4.6L Mustang Tech
Replies
4
Views
379
SN95 4.6L Mustang Tech Mar 10, 2026
kenster1092
K
SURGING IDLE / NO IDLE CHECKLIST FOR 1999–2004 MUSTANG GT (4.6L 2V) - Work In Progress
  • Noobz347
  • Aug 30, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
934
1996 - 2004 SN95 Mustang -General/Talk- Aug 30, 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?