Cannot fine problem new 02 sensor new fuel filter new coil paks, spark plugs, new map sensor and oil change.
May 2, 2017 at 8:44 PM
P0171 code
2003 CHEVROLET TRAILBLAZER
MELODY KEECH
- MEMBER
- 1 POST
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STEVE W.
- ✓ASE Certified Mechanic
- 15,200 POSTS
P0171 - System lean Bank 1 - Put a scan tool on it and watch the fuel trims. See if the issue is a vacuum leak (most likely), bad purge valve or other air leak by testing those as you watch the fuel trims. Check the fuel pump pressure as well, a weak pump can cause this.
Basically you need to actually see what the various sensors are sending to the ECM to diagnose this.
Coil packs and plugs will not cause a lean code. Misfires caused by those could however cause a rich code.
Basically you need to actually see what the various sensors are sending to the ECM to diagnose this.
Coil packs and plugs will not cause a lean code. Misfires caused by those could however cause a rich code.
May 2, 2017 at 10:30 PM
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