This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and therefore not compensated for and can thin the engine out and can furthermore allow the engine to rev stirring taking into account not desired causing severe running. As its a mechanical irregularity it tends not to point of view on the malfunction blithe and you can sometimes hear a hissing noise later the engine running.
Might along with be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can attain a fast fault find if you unplug the meter and rule the engine without it. if the engine condition is the thesame later chances are the meter or the association to it is faulty. Its also worth cleaning the MAF sensor wires, as they can get coated in imitation of dirt over become old which after that offsets the reading. Use some entry cleaner or brake cleaner to spray onto the wires to separate the dirt upon no account be adjacent to the wires subsequent to whatever as they are totally fragile
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you taking place to date upon every maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms stirring and is warmed up? oftentimes in engine measure many factors may cause the thesame symptom(s)