P0171

System Too Lean (Bank 1)

Severity: Medium Fuel & Air Metering Ford Specific Est. Repair: $80 - $400

Schedule diagnosis soon. Continued driving may worsen the issue.

What Does P0171 Mean?

Very common on many Ford engines. Often MAF contamination or vacuum leaks after the MAF.

Common Symptoms

CEL
Hesitation
Rough idle

Possible Causes

Dirty MAF
Vacuum leaks
PCV
Fuel delivery
Exhaust leak before O2

How to Fix P0171 – Repair Guide

Clean MAF carefully
Inspect intake tube clamps
Smoke test
Check fuel pressure
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Disclaimer: Information is for educational reference only and does not replace professional diagnosis. Actual causes and costs vary by vehicle make, model, year and condition. Always verify with a qualified technician.