Automotive diagnostics
Engine Fault Codes Reviewed: Are They Really Killing Your Fuel Efficiency?
Yes, a P0171 code typically trims fuel economy by roughly 3%, equating to about 1.5 extra gallons per 100 miles. Understanding the P0171 Engine Fault Code The P0171 code signals a “system too lean” condition on bank 1, meaning the engine control module (ECM) detects more air than fuel