How can I tell if my mass air flow sensor is bad

Diagnostic testing using a diagnostic tool suitable for monitoring of various related engine performance components is needed. I would say based off of your concerns the mass air flow sensor is not the biggest concern. The gray smoke could be related to oil consumption from the engine, especially if it's after the car sits. Fuel, spark and air intake should all be checked regarding the poor performance. www.repairpal.com/repair-shops