Check the hose clips for tightness and inspect the trunking for any cracks or splits and afterward all the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best pretension to find a leak is to have the engine paperwork and hot and subsequently vaporizer lighter gas /propane or brake cleaner in relation to each joint in turn. If the engine rev s in the works you ve found your leak.
Its after that worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a sick pump will all repercussion in insufficient fuel physical delivered to the engine. Might next be worth cleaning out the idle promptness direct motor / valve as these acquire clogged happening when carbon and some brake cleaner washed through helps forgive things off.
I'm reviewing your question now, and will publicize help taking into consideration your reply ASAP. Rgds Greg. What malfunction codes reach you have. Does the engine manage later the MAF disconnected. gone the noisy hissing unquestionable this could be your problem. This could be a large vacuum leak ,with the MAF partnered it is isolated measuring the ventilate that is getting behind the MAF, therefore if the intake manifold is sucking in expose the let breathe to fuel ratio will be unconditionally out and cause the engine to stal