This could be an airleak after the airflow meter, any expose dragged in here isn t seen by the ECU and as a result not compensated for and can thin the engine out and can moreover permit the engine to rev taking place taking into account not desired causing scratchy running. As its a mechanical defect it tends not to viewpoint on the fault lighthearted and you can sometimes hear a hissing noise afterward the engine running.
Might also be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can reach a fast defect find if you unplug the meter and direct the engine without it. if the engine condition is the thesame subsequently chances are the meter or the association to it is faulty. Its next worth cleaning the MAF sensor wires, as they can acquire coated subsequently dirt on top of mature which subsequently offsets the reading. Use some right to use cleaner or brake cleaner to spray onto the wires to separate the dirt on no account be adjacent to the wires with everything as they are no question fragile
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you taking place to date upon all maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms up and is warmed up? oftentimes in engine operate many factors may cause the similar symptom(s)