When your 2022 Colorado loses power and shows a P0171 code, the engine is running lean—it's getting too much air relative to fuel. This starves the engine of the fuel it needs for proper combustion, robbing you of power and potentially causing damage if ignored.
What P0171 Tells Us
The P0171 code stands for "System Too Lean (Bank 1)." On the Colorado's 2.5L inline-4 or 3.6L V6 (Bank 1 being the bank with cylinder 1), the engine control module has detected that it's adding more fuel than expected to maintain proper air-fuel ratios.
Symptoms of a Lean Condition
- Noticeable power loss, especially under acceleration
- Engine hesitation or stumbling
- Rough or high idle
- Difficulty starting
- Possible backfiring through the intake
- Increased engine temperature
- Poor fuel economy (counterintuitively)
Common Causes
- Vacuum leak: Cracked hoses, leaking intake manifold gasket, or brake booster leak
- Mass airflow sensor: Dirty or failing MAF reading incorrectly
- Fuel delivery issues: Weak fuel pump, clogged filter, or failing injector
- Air intake leak: Unmetered air entering after the MAF sensor
- Exhaust leak: Leak near the O2 sensor causes false readings
- PCV system fault: Stuck-open PCV valve or related vacuum leak
Diagnostic Process
- Scan for freeze frame data to understand conditions when the code set
- Check fuel trims—long-term fuel trim above +10% confirms the lean condition
- Inspect for vacuum leaks using carb cleaner or a smoke machine
- Check the MAF sensor readings and condition
- Verify fuel pressure is within specification
Repair Costs
- Vacuum hose repair: $50-$150
- Intake manifold gasket: $200-$500
- MAF sensor cleaning or replacement: $50-$300
- Fuel pump replacement: $400-$800
- Fuel injector service: $100-$400
- PCV valve replacement: $50-$150
Finding vacuum leaks can be time-consuming, so diagnostic labor may add $100-200 to any repair.