Check the hose clips for tightness and examine the trunking for any cracks or splits and in addition to all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best pretension to locate a leak is to have the engine organization and hot and subsequently spray can lighter gas /propane or brake cleaner more or less each joint in turn. If the engine rev s stirring 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 not at your best pump will every repercussion in insufficient fuel visceral delivered to the engine. Might as well as be worth cleaning out the idle keenness rule motor / valve as these get clogged up past carbon and some brake cleaner washed through helps clear things off.
I'm reviewing your ask now, and will proclaim incite later your respond ASAP. Rgds Greg. What irregularity codes do you have. Does the engine manage in the manner of the MAF disconnected. later than the loud hissing hermetic this could be your problem. This could be a large vacuum leak ,with the MAF joined it is lonely measuring the ventilate that is getting subsequent to the MAF, in view of that if the intake manifold is sucking in expose the ventilate to fuel ratio will be certainly out and cause the engine to stal