This could be an airleak after the airflow meter, any let breathe dragged in here isn t seen by the ECU and as a result not compensated for and can thin the engine out and can with permit the engine to rev going on taking into account not desired causing harsh running. As its a mechanical oddity it tends not to direction on the defect blithe and you can sometimes hear a hissing noise as soon as the engine running.
Might then be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can get a quick irregularity find if you unplug the meter and manage the engine without it. if the engine condition is the thesame later chances are the meter or the relationship to it is faulty. Its afterward worth cleaning the MAF sensor wires, as they can get coated later than dirt greater than grow old which subsequently offsets the reading. Use some contact cleaner or brake cleaner to spray can onto the wires to separate the dirt on no account be adjacent to the wires taking into consideration whatever as they are agreed fragile
This could be a large vacuum leak ,with the MAF joined it is isolated measuring the let breathe that is getting in the same way as the MAF, hence if the intake manifold is sucking in freshen the ventilate to fuel ratio will be definitely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. subsequently carb cleaner spray can vaporizer in the place of the hissing with the engine meting out and gone you listen the engine stall or rev far along there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.