P0171 code and stalles at stop

[zell66]

Recently replaced fuel pump and a section of fuel line. (work complete 2 months ago and put on 2000 miles) Yesterday check engine light came on and it gave me the code above and stalled every time I came to a complete stop.This is a 5.3 l non flex motor.

Any ideas or direction I can go to fix this vehicle. Thank s!!

 

[HiHoeSilver]

Recently replaced fuel pump and a section of fuel line. (work complete 2 months ago and put on 2000 miles) Yesterday check engine light came on and it gave me the code above and stalled every time I came to a complete stop.This is a 5.3 l non flex motor.

Any ideas or direction I can go to fix this vehicle. Thank s!!

Bank 1 lean code.

Check for vacuum leaks.
Check fuel pressure at the rail.

Do you have a scanner that you can see/ graph live or freeze frame data?

 

[zell66]

Well he is a conundrum....on a hunch filled tank and within 2 to 3 start and stop of engine, check engine light goes off and truck does not die at a stop. Could it be the fuel is sloshing around and fuel pump lost prime????

 

[HiHoeSilver]

Well he is a conundrum....on a hunch filled tank and within 2 to 3 start and stop of engine, check engine light goes off and truck does not die at a stop. Could it be the fuel is sloshing around and fuel pump lost prime????

How much gas did it take? Could have been bad gas or high ethanol content.

 

[swathdiver]

Recently replaced fuel pump and a section of fuel line. (work complete 2 months ago and put on 2000 miles) Yesterday check engine light came on and it gave me the code above and stalled every time I came to a complete stop.This is a 5.3 l non flex motor.

Any ideas or direction I can go to fix this vehicle. Thank s!!

Did you replace the pump itself or the entire assembly?

 

[zell66]

How much gas did it take? Could have been bad gas or high ethanol content.

it seemed to stall at just under a 1/4 tank. we use regular unleaded.

 

[zell66]

Did you replace the pump itself or the entire assembly?

I replaced the entire fuel pump assembly.

 

[HiHoeSilver]

it seemed to stall at just under a 1/4 tank. we use regular unleaded.

If it's not doing it now, I would run a couple tanks of premium through it and some fuel system cleaner. Techron or Kreen preferred.

 

[swathdiver]

Check intake gaskets and fuel trims next on that side.

 

[zell66]

A mechanic buddy of mine suggested it was the throttle body?

 

[HiHoeSilver]

A mechanic buddy of mine suggested it was the throttle body?

Not too likely with your symptoms. I would blame a dirty MAF before I messed with the throttle body, but either of those would translate on both banks. You are way more likely looking at a vacuum leak, a fuel delivery problem, or a bad o2 sensor.

 

[zell66]

i will try the O2 sensor and I am currently running a fuel cleaner through the system.

 

[HiHoeSilver]

i will try the O2 sensor and I am currently running a fuel cleaner through the system.

The fuel system cleaner is good either way. Beyond that, you need to see the scan data to make an educated move rather than just throw parts at it. Chances are that your sensor is fine and is just reporting on your real issue.

 

[gpracer1]

Try running the known good gas you have now until it gets low, if it does it again fill it all the way up (record number of gallons) and see if it is fixed again. It may be a fuel level problem, or reported fuel level like it says you have a 1/4 tank but its really emtpy-ish and you are running on fumes.
Could be fuel pickup issue.

 

[oldchev]

I agree.
If your problem exists when your fuel level shows under 1/4 then either your fuel is lower than you think or the fuel pick up is drawing air. If you have a fuel pressure tester (about $20 at HF) at the time symptoms are present, then attach the tester (if safe to do so) and check pressure. if its fluctuating you have one of the problems mentioned above.