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

running lean?

  • Thread starter Thread starter Bad92GT
  • Start date Start date May 14, 2006

Bad92GT

The 5 Minute Plan Man
Jun 10, 2004
492
0
0
SC
May 14, 2006
#1
  • May 14, 2006
  • #1
im kinda po'd about it.. why the hell does the car run lean immediately after i hit the throttle.. then it riches up a lil bit and saves itself.. then is strong again.. i adj the fpr like it should and it helped but not that much.. i have an h/c/i 24# injectors and all the bolt ons known to man.. could it be the tps sensor? someone hacked my harness and hardwired it in there.. i have a plug for the harness itself.. maybe replace it? i cleaned the IAC and no luck there.. it didnt do this before i built the motor.. what is the things to check in my cars case?
 

90mustangGT

I felt sorry for girls because
Founding Member
Jan 15, 2002
2,773
17
89
Dallas, GA
May 14, 2006
#2
  • May 14, 2006
  • #2
The TPS is the first sensor that tells the compuer what you are doing at the pedal, so if it were bad, there would be a delay in the fuel enrichment. Adjusting fuel pressure and such won't help it.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
May 14, 2006
#3
  • May 14, 2006
  • #3
Might we ask how you know you're going lean and then fattening back up?
 

Bad92GT

The 5 Minute Plan Man
Jun 10, 2004
492
0
0
SC
May 15, 2006
#4
  • May 15, 2006
  • #4
i hit the throttle and immediatly it sucks in the air.. as it does the car stumbles and then kicks itself back up and you smell fuel for a sec (rich).. making me think im not getting a correct air to fuel because of something or other.. once i get the car home from the shop, i'll check some things out
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
May 15, 2006
#5
  • May 15, 2006
  • #5
That's not the most reliable way to determine the stoichiometry - I thought you had a WB or were DL'ing or something.

The studder probably causes fuel to go unburned, which is what smells rich. But with an issue like that, you dont know if it's rich or lean when stumbling, and after that, who knows because of the initial issue.

If not mentioned, retrieving the codes is the first thing to do.

Good luck.
 
You must log in or register to reply here.

Similar threads

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
697
Fox 5.0 Mustang Tech Nov 9, 2025
Mustang5L5
Engine 1990 LX 5.0L EFI Mustang Fuel Management Problems - HELP!
  • 5.0LXStanger
  • May 25, 2025
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
45
Views
2K
Fox 5.0 Mustang Tech Jul 11, 2025
5.0LXStanger
S
Fox '87 GT can't get to stay running
  • spilly
  • Mar 29, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
26
Views
561
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Apr 25, 2026
CAMTWO1070
0
'04 V6 running rich excessively on both banks
  • 04DSGVert
  • Oct 26, 2025
  • SN95 V6 Mustang Tech
Replies
2
Views
287
SN95 V6 Mustang Tech Oct 27, 2025
04DSGVert
0
J
Engine No power after idle
  • JustinTilley86
  • Aug 10, 2024
  • Fox 5.0 Mustang Tech
  • 2
Replies
34
Views
2K
Fox 5.0 Mustang Tech Sep 23, 2024
General karthief
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?