I have got the following codes yesterday:P0170, P0171, P0300, P0301, P0302, P0303, P0304. I have a secondary air pump hose that is broken. Can it cause it? I also had timing belt replaced a few weeks ago. Not sure if it's related. Any recommendation on where to start?
Message was edited by: Techi
Random misfire (P0300, 1,2,3,4 are misfires on all four cylinders. P0171, P0170 (lean system). I would check:
Check Mass Air Flow Sensor (G70)
Check Fuel Pressure Regulation
Check Fuel Pump
Check Intake System for Leaks
Check Exhaust System for Leaks
Check Secondary Air System for Leaks
Check Vacuum hose for Leaks
Mass air flow might be the first check. Use VAC Com to see what kind of air flow what the sensor is seeing. They are a high failure rate item. VW usually has them priced pretty reasonable. I would recommend diagnosing the problem rather than wholesale replacing parts. You might also have a big vacuum leak or unmetered air entering the intake system.