This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and in view of that not compensated for and can thin the engine out and can afterward permit the engine to rev in the works similar to not desired causing scratchy running. As its a mechanical deformity it tends not to turn upon the oddity fresh and you can sometimes listen a hissing noise subsequent to the engine running.
Might furthermore be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can do a quick malformation locate if you unplug the meter and rule the engine without it. if the engine condition is the similar next chances are the meter or the connection to it is faulty. Its moreover worth cleaning the MAF sensor wires, as they can acquire coated behind dirt exceeding mature which later offsets the reading. Use some log on cleaner or brake cleaner to vaporizer onto the wires to remove the dirt on no account be adjacent to the wires when all as they are extremely fragile
I don't have any check engine lights unless I unplug the MAF sensor. once the MAF is plugged in subsequently the car will stall unless I put my foot on the accelerator. There is after that an intermittent popping unassailable coming at idle.