Fuel Economy is Down
Low Fuel Economy Today’s engine management systems rely on many different sensor inputs to regulate fuel economy, performance and emissions. Symptom: Poor Fuel Economy Probable Causes: Fuel Rich Codes (P0172 and/or P0175) Coolant Sensor (P0115 to P0119) Misfire Codes (P030x) Mass Air Flow (P0100 to P0105) Oxygen Sensor Codes (P0130 to P0167) or (P0036 to P0064) MAP Sensor (P0105 to P0109) With the price of gasoline, you don’t want to ignore this kind of problem for long. When fuel economy is down, you may find any number of codes: P0172 and/or P0175 are rich codes, and indicate a general rich air/fuel condition. The underlying cause may be anything that increases fuel delivery, such as excessive fuel pressure, a defective fuel pressure regulator, plugged return line, or leaky injectors. Decreased airflow from a dirty air filter or restricted air intake misleads the mass airflow sensor or engine management system into believing the engine is usin...