This could be an airleak after the airflow meter, any expose dragged in here isn t seen by the ECU and suitably not compensated for and can lean the engine out and can with permit the engine to rev stirring once not desired causing scratchy running. As its a mechanical anomaly it tends not to outlook on the oddity buoyant and you can sometimes listen a hissing noise afterward 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 do a fast irregularity find if you unplug the meter and direct the engine without it. if the engine condition is the thesame then chances are the meter or the relationship to it is faulty. Its moreover worth cleaning the MAF sensor wires, as they can acquire coated bearing in mind dirt higher than become old which after that offsets the reading. Use some right of entry cleaner or brake cleaner to spray onto the wires to sever the dirt on no account touch the wires following anything as they are utterly fragile
This could be a large vacuum leak ,with the MAF joined it is abandoned measuring the freshen that is getting once the MAF, correspondingly if the intake manifold is sucking in freshen the expose to fuel ratio will be no question out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. considering carb cleaner spray can vaporizer in the place of the hissing as soon as the engine executive and considering you hear the engine stall or rev superior there is the leak ,could be a bad vacuum hose bad gasket on the manifold.