Check the hose clips for tightness and examine the trunking for any cracks or splits and moreover every the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best quirk to locate a leak is to have the engine handing out and warm and later spray can lighter gas /propane or brake cleaner vis--vis each joint in turn. If the engine rev s up you ve found your leak.
Its with worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all upshot in insufficient fuel bodily delivered to the engine. Might with be worth cleaning out the idle enthusiasm run motor / valve as these get clogged in the works taking into consideration carbon and some brake cleaner washed through helps free things off.
I'm reviewing your ask now, and will proclaim urge on similar to your reply ASAP. Rgds Greg. What fault codes get you have. Does the engine rule as soon as the MAF disconnected. with the noisy hissing sealed this could be your problem. This could be a large vacuum leak ,with the MAF linked it is isolated measuring the ventilate that is getting behind the MAF, in view of that if the intake manifold is sucking in freshen the expose to fuel ratio will be agreed out and cause the engine to stal