This could be an airleak after the airflow meter, any air dragged in here isn t seen by the ECU and as a result not compensated for and can thin the engine out and can with permit the engine to rev going on similar to not desired causing scratchy running. As its a mechanical malformation it tends not to viewpoint on the deviation blithe and you can sometimes listen a hissing noise afterward 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 get a fast deformity locate if you unplug the meter and manage the engine without it. if the engine condition is the similar subsequently chances are the meter or the association to it is faulty. Its along with worth cleaning the MAF sensor wires, as they can acquire coated like dirt exceeding times which later offsets the reading. Use some edit cleaner or brake cleaner to spray can onto the wires to sever the dirt on no account be next to the wires next everything as they are totally fragile
I'm reviewing your question now, and will reveal help in imitation of your reply ASAP. Rgds Greg. What deformity codes realize you have. Does the engine direct past the MAF disconnected. past the loud hissing solid this could be your problem. This could be a large vacuum leak ,with the MAF related it is single-handedly measuring the let breathe that is getting gone the MAF, in view of that if the intake manifold is sucking in freshen the expose to fuel ratio will be unconditionally out and cause the engine to stal