This could be an airleak after the airflow meter, any expose dragged in here isn t seen by the ECU and so not compensated for and can thin the engine out and can then permit the engine to rev taking place taking into consideration not desired causing gruff running. As its a mechanical deviation it tends not to outlook upon the fault well-ventilated and you can sometimes hear a hissing noise in the same way as the engine running.
Might as a consequence be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can attain a quick malfunction find if you unplug the meter and run the engine without it. if the engine condition is the same then chances are the meter or the association to it is faulty. Its then worth cleaning the MAF sensor wires, as they can get coated next dirt over era which later offsets the reading. Use some right to use cleaner or brake cleaner to vaporizer onto the wires to remove the dirt upon no account touch the wires taking into consideration everything as they are utterly fragile
This could be a large vacuum leak ,with the MAF linked it is by yourself measuring the freshen that is getting afterward the MAF, fittingly if the intake manifold is sucking in ventilate the expose to fuel ratio will be categorically out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. following carb cleaner spray spray in the area of the hissing once the engine meting out and taking into consideration you listen the engine stall or rev highly developed there is the leak ,could be a bad vacuum hose bad gasket on the manifold.