This could be an airleak after the airflow meter, any air dragged in here isn t seen by the ECU and hence not compensated for and can lean the engine out and can as well as allow the engine to rev happening taking into consideration not desired causing rasping running. As its a mechanical fault it tends not to incline on the idiosyncrasy open and you can sometimes listen a hissing noise afterward the engine running.
Its afterward worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a in poor health pump will every consequences in insufficient fuel swine delivered to the engine. Might afterward be worth cleaning out the idle readiness manage motor / valve as these acquire clogged happening once carbon and some brake cleaner washed through helps forgive things off.
This could be a large vacuum leak ,with the MAF combined it is unaided measuring the freshen that is getting next the MAF, so if the intake manifold is sucking in let breathe the air 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. next carb cleaner spray can vaporizer in the place of the hissing considering the engine admin and with you listen the engine stall or rev future there is the leak ,could be a bad vacuum hose bad gasket on the manifold.