This could be an airleak after the airflow meter, any air dragged in here isn t seen by the ECU and appropriately not compensated for and can lean the engine out and can in addition to permit the engine to rev in the works taking into consideration not desired causing unfriendly running. As its a mechanical irregularity it tends not to slope on the irregularity well-ventilated and you can sometimes hear a hissing noise taking into consideration the engine running.
Its along with worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a not a hundred percent pump will every outcome in insufficient fuel swine delivered to the engine. Might in addition to be worth cleaning out the idle speed control motor / valve as these acquire clogged going on subsequently carbon and some brake cleaner washed through helps free things off.
This could be a large vacuum leak ,with the MAF combined it is isolated measuring the let breathe that is getting next the MAF, for that reason if the intake manifold is sucking in ventilate the expose to fuel ratio will be agreed out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. in the same way as carb cleaner vaporizer spray can in the area of the hissing once the engine management and with you listen the engine stall or rev far along there is the leak ,could be a bad vacuum hose bad gasket on the manifold.