Codes po171/ and po175

2003 FORD F-150
200,000 MILES • 4.2L • V6 • 2WD • MANUAL
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JASONR#24
  • MEMBER
  • 1 POST
po171-Bank 1 too lean and po175-Bank 2 too rich. The truck has very low if any acceleration. I have to help shifting gears by pressing and releasing the gas pedal. When at idle stop, you can smell exhaust fumes.
Hopefully someone has the answer.
Jul 19, 2021 at 12:33 AM
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SQM
  • ✓Experienced Mechanic
  • 6,383 POSTS
Hello,

This issue can happen for several reasons.
It could be a defective MAF sensor, faulty fuel pressure regulator, restricted fuel line, air leak after the MAF sensor, etc. It could even be for a vacuum leak.

I have attached a diagnostics chart for the P0171 and P0175 code for your reference.
Please have a look at and should be able to narrow down the issue.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please let me know of any questions.

Thank you.
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Jul 19, 2021 at 2:59 AM
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