The codes come back running rich and running lean?

Tiny
ROBEDMISTON
  • MEMBER
  • 1994 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 129,000 MILES
After the truck has been running and up to operating temp the CEL starts coming on. The codes come back running rich and running lean. For the most part truck runs fine, but when warm and the CEL comes on the truck losses power and the it will pick back up and run ok
Wednesday, October 14th, 2009 AT 9:58 AM

1 Reply

Tiny
SQM
  • MECHANIC
  • 6,383 POSTS
Hello,

This could be due to a failing manifold absolute pressure sensor (MAP).
The MAP sensor controls the air fuel ratio.
Depending on the air flow it regulates the amount of fuel that engine will need.

A faulty sensor can trigger both rich or lean fuel mixture. This will also lead to sluggish acceleration and bad fuel mileage.

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.
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Tuesday, December 21st, 2021 AT 7:51 PM

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