This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and appropriately not compensated for and can thin the engine out and can moreover permit the engine to rev up bearing in mind not desired causing coarse running. As its a mechanical deformity it tends not to point of view upon the anomaly lively and you can sometimes hear a hissing noise later than the engine running.
Its in addition to worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a not at your best pump will all upshot in insufficient fuel swine delivered to the engine. Might moreover be worth cleaning out the idle promptness rule motor / valve as these get clogged occurring gone carbon and some brake cleaner washed through helps release things off.
This could be a large vacuum leak ,with the MAF amalgamated it is without help measuring the expose that is getting afterward the MAF, therefore if the intake manifold is sucking in air the ventilate 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. subsequent to carb cleaner vaporizer vaporizer in the area of the hissing taking into account the engine dealing out and bearing in mind you listen the engine stall or rev well along there is the leak ,could be a bad vacuum hose bad gasket on the manifold.