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

NEED HELP! Hesitation problem!

  • Thread starter Thread starter btsclan
  • Start date Start date Sep 24, 2008
B

btsclan

Member
Feb 22, 2004
64
0
6
Seattle, WA
Sep 24, 2008
#1
  • Sep 24, 2008
  • #1
Last weekend, I replaced my exhaust, headers to tailpipes, well after the install I noticed a hesitation that only happens under load. The car idles just fine but when I drive it and give it gas it misses and hesitates as the rpm's climb.

I replaced the cap/rotor, plugs, wires, and will replace the fuel pressure regulator tomorrow. I cant understand why its misses and hesitating. The last few weeks before I did the exhaust I felt a few times when the engine misses and hesitates under load but now its much much worse, maybe the new exhaust made the problem bigger. Any ideas would be greatly appricated! Could be a bad distributor or coil?? Help!!!
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Sep 24, 2008
#2
  • Sep 24, 2008
  • #2
Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical





If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.



The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.



The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see EQUUS DIGITAL FORD CODE READER (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
 
You must log in or register to reply here.

Similar threads

T
Engine Need help figuring out misfire and backfire
  • trystancounts
  • Sep 25, 2025
  • Fox 5.0 Mustang Tech
Replies
8
Views
302
Fox 5.0 Mustang Tech Sep 26, 2025
Noobz347
M
Engine Unexplainable Exhaust Pop and Gurgle
  • Mrnissen122
  • Feb 14, 2026
  • Fox 5.0 Mustang Tech
Replies
12
Views
593
Fox 5.0 Mustang Tech Feb 18, 2026
Noobz347
S
Engine 1990 5.0 bogs and pops over half throttle
  • Sander
  • Aug 1, 2025
  • Fox 5.0 Mustang Tech
Replies
4
Views
362
Fox 5.0 Mustang Tech Aug 2, 2025
AeroCoupe
L
Help with 1986 GT 5 Speed Please
  • Lcasada1999
  • Mar 20, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
7
Views
268
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 21, 2026
CAMTWO1070
P
Progress Thread New To Me 1988 GT - trying to set up vacuum lines for upper intake question
  • pindude80
  • May 6, 2025
  • Fox 5.0 Mustang Tech
  • 9 10 11
Replies
214
Views
14K
Fox 5.0 Mustang Tech Mar 28, 2026
pindude80
P
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?