This could be an airleak after the airflow meter, any freshen dragged in here isn t seen by the ECU and for that reason not compensated for and can lean the engine out and can in addition to permit the engine to rev up past not desired causing coarse running. As its a mechanical aberration it tends not to point on the malfunction light and you can sometimes listen a hissing noise afterward the engine running.
Its moreover worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a under the weather pump will every result in insufficient fuel bodily delivered to the engine. Might furthermore be worth cleaning out the idle rapidity rule motor / valve as these get clogged going on taking into account carbon and some brake cleaner washed through helps free things off.
This could be a large vacuum leak ,with the MAF related it is lonesome measuring the let breathe that is getting past the MAF, as a result if the intake manifold is sucking in freshen the let breathe to fuel ratio will be unconditionally out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. subsequent to carb cleaner spray can vaporizer in the area of the hissing as soon as the engine government and behind you listen the engine stall or rev difficult there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.