P0171 code has been showing up (System too Lean)

Tiny
TLARMA
  • MEMBER
  • 2007 CHEVROLET TRAILBLAZER
  • V6
  • 2WD
  • AUTOMATIC
  • 138,000 MILES
For a little over a month, P0171 (System to Lean) code comes up. My brother has cleaned the throttle and the MAF. It then worked fine for a few weeks, then the code came up again and the sputtering started. He took it to O'Reilys Auto Parts. They had said since you removed the throttle and put it back in, it would need to retrain itself. He then removed it again and cleaned out other parts in the car. Just the other day, my car started sputtering again in the morning. It runs fine the rest of the day. Also, when I was out of town the other day, my car sat for about four days with a low tank of gas. When we were traveling on the highway, my reduced power engine light came on. Once I filled up with gas it was fine. I am just trying to see what could be the problem. Do I need a new O2 sensor, a change of the manifold gasket, fuel injector cleaning? Not sure. The car is good to drive, but would like to fix this problem.
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Wednesday, July 6th, 2016 AT 7:41 AM

4 Replies

Tiny
HMAC300
  • EXPERT
It does not need to retrain it does it while it is driving and computer does that not tbi. check fuel pressure with a gauge auto parts rent it.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
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Wednesday, July 6th, 2016 AT 8:08 AM
Tiny
TLARMA
  • MEMBER
Thanks. My brother is out of town. The vehicle seems fine to drive. I am okay driving it for now.
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Wednesday, July 6th, 2016 AT 8:16 AM
Tiny
KEN
  • ADMIN
Hi TLARMA,

It sounds like you could need spark plugs, if the engine misfires it will set a code for the lean p0171

Here is a couple of guides to help you

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

and

https://www.2carpros.com/articles/how-to-change-spark-plugs

Let me know what you find out

Best, Ken
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Thursday, July 7th, 2016 AT 4:36 PM
Tiny
RENEE
  • ADMIN
Hi TLARMA,

Here is a link to an article from this site that features written instructions and pictures showing and explaining the process of checking the fuel pressure yourself. If you decide you would like do this yourself you can purchase an inexpensive fuel pressure gauge online from sites like Amazon.com. For your convenience I have included a link to Amazon.com fuel pressure gauge page.

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

https://www.amazon.com/gp/search/ref=as_li_qf_sp_sr_il_tl?ie=UTF8&tag=2carprcom20&keywords=Fuel_pressure_gauge&index=aps&camp=1789&creative=9325&linkCode=xm2&linkId=605f3a92fb400af06465c1566134514b

Thank you for visiting 2CarPros.

Kindest regards,

Renee
Admin
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Thursday, July 7th, 2016 AT 4:40 PM

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