This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and so not compensated for and can lean the engine out and can after that allow the engine to rev up when not desired causing sharp running. As its a mechanical fault it tends not to outlook on the defect blithe and you can sometimes listen a hissing noise when the engine running.
Its as well as 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 all upshot in insufficient fuel physical delivered to the engine. Might also be worth cleaning out the idle enthusiasm direct motor / valve as these acquire clogged up gone carbon and some brake cleaner washed through helps forgive things off.
This could be a large vacuum leak ,with the MAF associated it is and no-one else measuring the freshen that is getting bearing in mind the MAF, so if the intake manifold is sucking in air the expose to fuel ratio will be no question out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. considering carb cleaner vaporizer vaporizer in the area of the hissing in the manner of the engine handing out and in imitation of you hear the engine stall or rev sophisticated there is the leak ,could be a bad vacuum hose bad gasket on the manifold.