• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Call for help- misfire and lean bank 2

  • Thread starter Thread starter 1fast03pony
  • Start date Start date Sep 10, 2006

1fast03pony

Member
Jul 1, 2003
749
0
17
New york
Sep 10, 2006
#1
  • Sep 10, 2006
  • #1
Guys- im a few days away from installing my KB, and this happens

I put in my full bbk exhaust last weekend. Longtubes, o/r X with my existing magnapacks.

On cold starts, she stumbles for a good 3 minutes. Its a clear surging of power while driving and it just feels like ****. Then she'll even out after a while. I just filled up with fresh gas so im gonna see tomorrow if she does it again. However....
My light tripped again (not cats this time) and it read p0174 which is the lean bank 2 code. What do I check, and should i even worry since ill be putting in the KB with the KB chip, and a custom dyno tune coming next week?

I cleared the code with the xcal2

EDIT

I just did a quick search, and I shouldve mentioned that i recently replaced the drivers side front o2 sensor because the stock one was cross threaded in my old x pipe. Can this mean the o2 sensor is bad? Its brand new bosch.

 

Mike97gt

it doe snot
Founding Member
Jan 26, 1999
10,633
7
89
the people's republic of massachusetts
Sep 10, 2006
#2
  • Sep 10, 2006
  • #2
bank 2 is the drivers side.. so if your 02 sensor is not threaded in properly that can cause issues like this.. another possiblitity is a misfire on bank 2 is causing that bank to read lean because of all the unburned oxygen being dumped from the misfire. Sometimes you will not get a misfire code because the misfire monitor was not ready, if the battery was disconnected or the keep alive memory was recently reset then the misfire monitor might not work.
 

fastangboi

My first set of nuts vibrated themselves off.
Jul 26, 2006
274
0
0
Slowville
Sep 10, 2006
#3
  • Sep 10, 2006
  • #3
check out your spark plugs and make sure they are doin ok.
 
N

nl mex

New Member
Sep 24, 2004
59
0
0
Bakersfield, Cali
Sep 10, 2006
#4
  • Sep 10, 2006
  • #4
I've struggled with a problem similar to this, but mine has to do with one or more of the coils being bad. I need to get around to fixing it.
 

Stang|ess

seeking cyber partner(s)
Oct 18, 2003
941
0
37
Hawaii
Sep 10, 2006
#5
  • Sep 10, 2006
  • #5
Replace the o2 sensor with an OEM ford.

Are your LTs ceramic coated? I've been reading that if you dont get them coated, it will cause a CEL until the pipes get hot
 

triggz

Founding Member
May 15, 2002
1,218
0
37
Gadsden, AL
Sep 10, 2006
#6
  • Sep 10, 2006
  • #6
Swap coils and see if the problem follows to the cylinder you swap with. Then swap injectors and see if it follows that.. If thats no help, try a compression test on (at least) that cylinder, the 2 near it, and for reference one on the other bank. FWIW, the last romeo engine I did a comp check on showed 180psi.

Nothing wrong with running a bosch sensor, thats what you're buying from ford with a motorcraft logo on it.


What stang|ess is referring to is the LTs have no pre-heaters (that first set of cats) and it takes the exhaust temps longer to reach the operating range of the O2s.
 

Mike97gt

it doe snot
Founding Member
Jan 26, 1999
10,633
7
89
the people's republic of massachusetts
Sep 11, 2006
#7
  • Sep 11, 2006
  • #7
I just re read this and now I see there is a new 02 sensor on the drivers side that is not cross threaded ?

Ok well that sensor SHOULD be ok, 99-100 times a code like this is not caused by the 02 sensor itself.. since you said it feels like it's misfiring then it probally is on bank 2. this is why you are getting a lean reading from that bank.. When you get a misfire you are dumping unburned 02 down the exhaust, since the sensor can not see the unburned fuel it sees the exhaust gasses as lean..

you need to figure out the misfire, mot common causes of a misfire on these cars is a plug or coil
 
You must log in or register to reply here.

Similar threads

M
Help! 2003 GT misfire when hot
  • Modular03
  • Feb 10, 2026
  • SN95 4.6L Mustang Tech
Replies
4
Views
387
SN95 4.6L Mustang Tech Feb 13, 2026
Mustang5L5
F
Trouble Shooting Sudden Shift of AFR at low RPM
  • Farva_84
  • Jun 6, 2025
  • SN95 4.6L Mustang Tech
Replies
8
Views
487
SN95 4.6L Mustang Tech Jun 8, 2025
Farva_84
F
I
Engine Insane fuel trims +25% LTFT Bank 1, -16% LTFT Bank 2
  • imw_stl
  • Aug 31, 2025
  • SN95 4.6L Mustang Tech
Replies
2
Views
295
SN95 4.6L Mustang Tech Sep 19, 2025
Mustang5L5
T
Looking for some help with 2006
  • thedudeillest
  • Mar 16, 2026
  • 2005 - 2014 S-197 Mustang -General/Talk-
Replies
14
Views
456
2005 - 2014 S-197 Mustang -General/Talk- Mar 20, 2026
Noobz347
Tuners come on inside
  • squeak93
  • Feb 13, 2026
  • SVT Tech Forum
Replies
1
Views
254
SVT Tech Forum Feb 20, 2026
squeak93
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L 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?