Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
While the lean code can be caused by a faulty MAF sensor and/or weak fuel pump, a MAF sensor code wont be caused by a weak or faulty fuel pump.
Lean codes are generally caused by a vacuum leak, weak fuel pressure, intake air leak, faulty or dirty MAF sensor, or intake manifold leak.
MAF codes are generally set by a faulty MAF sensor, vacuum leak, faulty PCV valve, open or short in MAF sensor wiring harness or connector.
First, check for vacuum leaks, including the intake manifold and throttle body. Spray around base of intake manifold with carb cleaner while engine is idling. If idle changes, replace intake manifold gasket.
If no leaks, then perform the following tests to determine whether MAF sensor is bad, or a wiring issue:
Click to open and download> Fuel pressure test