A bad mass air flow sensor can cause problems such as engine hesitation, engine stalling, engine running rich, lack of power, poor accelerating, hard starting or no starting.
The mass air flow sensor controls the fuel to air mixture ratio and lets the computer know how much fuel to send through the injectors when it's needed.
The bad mass air flow sensor may cause too much fuel to get through the injectors and cause the engine to run too rich.
If you unplug the mass air flow sensor and the engine runs better then the mass air flow sensor is likely bad and needs replaced.
You could drive with a bad mass air flow sensor but it's not recommended to do so.
If you drive with a bad mass air flow sensor your car or vehicle will likely stall, run lean under load or run rich at idle and your vehicle will use more fuel and your engine will lose performance.
A proper working mass air flow sensor is essential to a properly running and fuel efficient engine.
Getting your mass air flow sensor replaced will make your car run much better, improve your fuel mileage and your car will have more horsepower as a result.