Check the hose clips for tightness and examine the trunking for any cracks or splits and then every the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best showing off to find a leak is to have the engine doling out and warm and subsequently spray lighter gas /propane or brake cleaner roughly speaking each joint in turn. If the engine rev s in the works you ve found your leak.
Its along with 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 result in insufficient fuel monster delivered to the engine. Might along with be worth cleaning out the idle eagerness govern motor / valve as these get clogged stirring when carbon and some brake cleaner washed through helps clear things off.
This could be a large vacuum leak ,with the MAF linked it is without help measuring the freshen that is getting with the MAF, as a result if the intake manifold is sucking in air the ventilate to fuel ratio will be agreed out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. gone carb cleaner vaporizer spray can in the place of the hissing taking into account the engine meting out and following you hear the engine stall or rev superior there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.