Check the hose clips for tightness and examine the trunking for any cracks or splits and next every the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best exaggeration to find a leak is to have the engine giving out and warm and next spray lighter gas /propane or brake cleaner in this area each joint in turn. If the engine rev s taking place you ve found your leak.
Its next 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 every result in insufficient fuel being delivered to the engine. Might next be worth cleaning out the idle zeal control motor / valve as these acquire clogged going on when carbon and some brake cleaner washed through helps free things off.
I'm reviewing your question now, and will proclaim assist in the manner of your answer ASAP. Rgds Greg. What anomaly codes complete you have. Does the engine rule subsequent to the MAF disconnected. with the loud hissing hermetic this could be your problem. This could be a large vacuum leak ,with the MAF linked it is deserted measuring the let breathe that is getting taking into consideration the MAF, in view of that if the intake manifold is sucking in let breathe the expose to fuel ratio will be definitely out and cause the engine to stal