my 2003 Nissan runs good for a couple of hours then the speed decreases and sometimes will take a while to start,i was told that it could be the mass airflow sensor.
My car has an automatic transmission.
Hello. There are quite a few things that will cause this vehicle to stall. Most commonly though the issue is not the air flow sensor, but instead it is the crankshaft position sensor. This sensor is the input to the computer about engine speed. If the computer loses this signal then the engine will stall. This sensor typically starts to fail intermittently on this vehicle which will cause this. If you need to have this stalling issue checked out, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the car is stalling] https://www.yourmechanic.com/services/car-is-stalling-inspection
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing