99-04 Gt, Calling All Mechanical Bug Wizards

TheJarlofNewEdge

New Member
Feb 8, 2017
6
0
1
22
New tadpole in the pond here
But I am having some problems, i've thought long and hard about, but i live in the boonies, the mechanical experience is around here but i can't seem to come to a conclusion

- had stock gt w/K&N intake
- running fine

- installed pypes o/r H
- tried eliminators, didnt work
- installed tune, helped but now when i cold start it, itll rev @ 1000 for a moment, and when i want to drive off, it has no power when i want to give the engine any actual load, i give it 3/4 throttle for about two seconds and it feels like it switches over to spit enough fuel again, and the horses return
- other times, about 6/10 drives, give or take, ill get to a stop sign, doing fine idling cold starting it, and itll want to just die on the way down the road, perse, if i was 100%ing the clutch

- one other thing, my rear o2's are registering a lean code, im assuming my car is running rich
- my SCT is supposed to turn those off, why does it come back?

I can retune and have no CEL for about an hour, and then it comes right back up.

Im thinking o2 spacers.

I love my car brothers, can anyone step up to the plate to save Sally's life?

I want her to be my daily driver,
My track car.
My everything.
<3
 

Attachments

  • Sponsors(?)


Davedacarpainter

I think I've messed my pants
SN Certified Technician
Nov 28, 2015
11,965
11,460
193
58
Discordia
Welcome to stangnet.

I'll move your thread over to the '96-'04 tech subforum. That way you won't have to retype.

Look around the subforums for your type of mustang, you'll find lots of help there.
 

squeak93

10 Year Member
Jun 2, 2005
2,144
324
164
37
Joplin, Missouri
What codes specifically is it throwing? The rears need the sensor and the heater turned off in order to run an off road pipe and not trigger a cel. They will have little to no effect on the issues you're stating though.

I would suspect that you have a significant exhaust leak that is tossing a lean code (rear o2 will only tell if the cat is working, the front are what trim the fuel).

IF it only does the weird idle with the tune then you need to adjust the idle air motor in the tune to compensate either way.

Post the codes
 

TheJarlofNewEdge

New Member
Feb 8, 2017
6
0
1
22
What codes specifically is it throwing? The rears need the sensor and the heater turned off in order to run an off road pipe and not trigger a cel. They will have little to no effect on the issues you're stating though.

I would suspect that you have a significant exhaust leak that is tossing a lean code (rear o2 will only tell if the cat is working, the front are what trim the fuel).

IF it only does the weird idle with the tune then you need to adjust the idle air motor in the tune to compensate either way.

Post the codes

P1131 & P1151, both lean codes if i remember correctly, it couldn't be an exhaust leak, I just had it checked out at two different shops a month ago, no leaks whatsoever, I even replaced my RH gasket, which helped a LITTLE bit, but not much, turns out it had the smallest leak on it, but the problems presume.
 

squeak93

10 Year Member
Jun 2, 2005
2,144
324
164
37
Joplin, Missouri
p1131 is the bank two (driver side) sensor one (upstream) issue. Replace that sensor.

p1151 is related to a lean condition that is likely caused by the sensor not working.

Replace both sensors and report back.
 

TheJarlofNewEdge

New Member
Feb 8, 2017
6
0
1
22
If i were to take them off, and test them, what should they be throwing as far as voltage goes?

How would I test them, actually?

Any brand you recommend, or should I go all Motorcraft?
Sites you'd recommend?

Aaaaand, did you mean for me to replace both front sensors?

Or the LH rear also?
 
Last edited:

squeak93

10 Year Member
Jun 2, 2005
2,144
324
164
37
Joplin, Missouri
Bosh, buy from autozone/oriellys pep boys. Any of the normal parts stores will stock them.

Ignore the rears. Just replace the fronts. Do both, if one has an issue the other could fail as well.

I'm sure you could test them for load or impedance, I have no idea how. If you don't know the age of the sensors, it's best to just replace them, especially with the codes they are tossing up. Should be right around $100 for both.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,818
501
194
Houston Texas
Are you using anti-foulers/spacers on the front O2 sensors? If so, likely this is one of the sources of the problems.

This thread does not state the model year of the Mustang. Why is this important? Because the later MY Mustang have a smarter PCM. There's a subroutine that runs from time to time that forces a misfire just to confirm that is seen by the rear O2 sensor. This subroutine was put into place specifically to combat the use of MIL eliminators or anti-foulers on the rear O2 sensors.

Another source of front O2 sensor problems is when long tube headers are used and the O2 sensors are located to far down. There isn't enough heat to allow the O2 sensors to work correctly.

Bottom line. IF there's even the smallest exhaust leak, EXPECT problems with the O2 sensors.​
 

TheJarlofNewEdge

New Member
Feb 8, 2017
6
0
1
22
Are you using anti-foulers/spacers on the front O2 sensors? If so, likely this is one of the sources of the problems.

This thread does not state the model year of the Mustang. Why is this important? Because the later MY Mustang have a smarter PCM. There's a subroutine that runs from time to time that forces a misfire just to confirm that is seen by the rear O2 sensor. This subroutine was put into place specifically to combat the use of MIL eliminators or anti-foulers on the rear O2 sensors.

Another source of front O2 sensor problems is when long tube headers are used and the O2 sensors are located to far down. There isn't enough heat to allow the O2 sensors to work correctly.

Bottom line. IF there's even the smallest exhaust leak, EXPECT problems with the O2 sensors.​


- 04 Engine, '00 body (no idea about the computer in it though)
- im not using spacers on the upstreams haha
- just ordered new upstream o2s
- pypes o/r H

and i just have the rear o2s turned off with a tune

das awl
 
Last edited:
Thread starter Similar threads Forum Replies Date
G What’s this transmission part called? 1996 - 2004 SN95 Mustang -General/Talk- 2
M manual calls for 6qts what should dipstick read 1996 - 2004 SN95 Mustang -General/Talk- 1
Carson93Fox Fox What's it called 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 5
T What is this silver part called? 2005 - 2014 S-197 Mustang -General/Talk- 7
Noobz347 Temp Thread, Calling in Reinforcements to Change my TV Channel! :D 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 9
tannerc91gt Roll call 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 26
Edbert Remember when the Probe was almost called the Mustang? 1965 - 1973 Classic Mustangs -General/Talk- 4
RangerJoe Calling Turbo Guys! 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 42
T What is this called? 2005 - 2014 S-197 Mustang -General/Talk- 6
G What is this plastic piece called? Holds together throttle and tv cable 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 5
A Fox Calling All Engine Builders 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 20
M I Need Help But What Is This Part Called ??? SN95 V6 Mustang Tech 12
F Maximum Motorsports Customer Service - Did I Call On An Off Day?/please Help. 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 5
Christian Cornwell What Are These Called 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 5
9 Calling Convertible Top Experts Fox 5.0 Mustang Tech 14
35thGTLimited What Is This Wire Called, So I Can Replace? Goes From Alt To Battery. SN95 4.6L Mustang Tech 2
D Busted Chassis Part. What Is It Called? Fox 5.0 Mustang Tech 17
M Slow Oil Leak From This Plug, What's It Called? 1996 - 2004 SN95 Mustang -General/Talk- 10
E Roc What Is This Part Called And Where Can I Buy Replacement ? 1996 - 2004 SN95 Mustang -General/Talk- 1
Benz510 Fox What Is That Part Called That Connects To The Oem H Pipe? 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 13
R Manual Calls For Oil Pressure Of15 Psi @ 2000 Rpm ? 2005 - 2009 Specific Tech 5
74stang2togo Mustang Il Member Roll Call 1974 - 1978 Mustang II Talk & Tech 34
hoopty5.0 My Wife Called Me A Hoarder. 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 25
RangerJoe Hp Tv, Or What Ever They Call It These Days... 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 0
CarMichael Angelo It Shoulda Been Called A Mach1 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 56
Madd_Hatter_1979 Calling All Rear Suspension Gods! 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 42
mustangguy65 What Are These Called 1965 - 1973 Classic Mustangs -General/Talk- 5
F I Am What You Would Call New Old Stock. The Welcome Wagon 3
90lxwhite What's This Called? 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 6
J What Is This Called? Door Stop, Pin, Guide, Etc? (pic) 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 15
stangboy Fox Call Everybody Running 315s On A 10.5" Rim Without Minitubs 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 20
gtthomas Calling All Vortech Mustangs! Need Help 1996 - 2004 SN95 Mustang -General/Talk- 7
90lxwhite Calling All 4cyl Guys 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 6
striker911411 Calling All Part Cars. I Need A Bolt. 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 9
S Calling On The Expects, I Can't Figure It Out 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 1
SMOKEDYA Calling Almost Stock 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 2
95BlueStallion Calling Mad Mike 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 10
DADDYJUSTANG South West Dyno Day in Mandeville , La. Calling all southern Louisiana mustangs Regional Forums and Event Information 0
Vaz88GT What are the Stock Fox GT wheels called? 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 11
TOOLOW91 Calling TMI !!! I have a question for you guys 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 4
90lxwhite What Is The T Called That Has The Vac Lines Such As Ac And Ps On It 1994 - 1995 Specific Tech 6
horseballz Calling 2+2gt/distributor Curve Classic Mustang Specific Tech 6
theStangDoc Calling All Ponies Classic Mustang Specific Tech 4
Night Shifter Quick shout out to last call racing 1996 - 2004 SN95 Mustang -General/Talk- 3
F need help ASAP with compression-CALLING ALL EXPERTS Fox 5.0 Mustang Tech 1
B Need Advice Quick Please! - Car at Ford Waiting for me to call back SN95 4.6L Mustang Tech 20
N Calling all track guys for suspension advice. SN95 4.6L Mustang Tech 2
D Calling all 96-98 S/C Cobras SVT Tech Forum 0
CarMichael Angelo Escort, Call girl, or Crack Whore 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- 18
B Calling 5 Mustang Vert's Regional Forums and Event Information 0
Similar threads