OBD code P0171, will not start

2006 CHEVROLET TRAILBLAZER
130,000 MILES • 4.2L • 6 CYL • 4WD • AUTOMATIC
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JDUNFORD2871
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  • 1 POST
Truck cranks so I'm pretty sure the battery is strong. But it won't start. Seems like it's not getting fuel. It was running fine the night before and I went out in the morning and nothing.
Feb 6, 2020 at 4:59 AM
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JOETECHPRO
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  • 705 POSTS
Hey JDUNFORD2871,

OBD code P0171 points to fuel system too lean, this would point towards a fuel pressure problem.

If the engine is turning over slowly then trying to boost with jumper cables or a jump pack will rule out a low battery state of charge.

A quick test to attempt to see if the fuel pump has stopped working would be to tap the bottom of the fuel tank whilst someone is cranking the motor. Using a rubber/wooden mallet or something that will not dent the tank. This can sometimes shock the pump and get it going. You then know you have a fuel pump issue.

Let me know how this goes. The next step will be to check fuel pressure.
Do you have access to a gauge for this?

Regards, Joe
Feb 6, 2020 at 8:51 AM
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STRAILER
  • ✓Experienced Mechanic
  • 55,721 POSTS
Here is a guide to help you as well:

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

Please run down this guide and report back.
Feb 9, 2020 at 2:46 AM
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