2003 Ford Expedition Sensor says running lean and has a hes

Tiny
RFLAT
  • MEMBER
  • 2003 FORD EXPEDITION
  • V8
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
My check engine light came on and I had it checked. The code said that my engine was running lean. At the same time the front AC stopped blowing and the car picked up a bad hesitation, not sure if these are related. The hesitation does not happen all of the time, just randomly. We could hear a vaccum leak coming from the elbow hose at the pcv valve. Changed that hose, but it didn't fix the problem. I also changed the mass air flow sensor, but it did not help either. After I changed these parts out I took it back and had the code cleared. It showed back up the next day and read the same thing. Running lean. Thanks for your help.
Thursday, October 8th, 2009 AT 8:44 AM

3 Replies

Tiny
OBXAUTOMEDIC
  • MECHANIC
  • 3,711 POSTS
Hello,

Here is a link to check out it will give you info on lean mixture codes for both bank 1 and/or bank 2.

https://www.2carpros.com/first_things/why_does_my_engine_have_a_lean_mixture_code.htm
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Thursday, October 8th, 2009 AT 9:02 AM
Tiny
RFLAT
  • MEMBER
  • 2 POSTS
Actually hooked it up to the computer again last night and it said cylinder number 3 was misfiring in first 1000 rpm's. Any ideas on what could be causing it? Thanks.
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Friday, October 9th, 2009 AT 8:17 AM
Tiny
OBXAUTOMEDIC
  • MECHANIC
  • 3,711 POSTS
Here is something to try.

Swap the #3 coil with another one and see if the Misfire moves to that cylinder if so replace the coil and boot.

.
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Friday, October 9th, 2009 AT 8:17 PM

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