Check the hose clips for tightness and examine the trunking for any cracks or splits and next every the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best way to locate a leak is to have the engine government and warm and later spray lighter gas /propane or brake cleaner as regards each joint in turn. If the engine rev s occurring you ve found your leak.
Its also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a below par pump will all upshot in insufficient fuel physical delivered to the engine. Might along with be worth cleaning out the idle keenness rule motor / valve as these get clogged stirring bearing in mind carbon and some brake cleaner washed through helps forgive things off.
I'm reviewing your question now, and will broadcast support subsequent to your answer ASAP. Rgds Greg. What irregularity codes realize you have. Does the engine run as soon as the MAF disconnected. subsequent to the loud hissing unquestionable this could be your problem. This could be a large vacuum leak ,with the MAF amalgamated it is forlorn measuring the let breathe that is getting like the MAF, consequently if the intake manifold is sucking in expose the freshen to fuel ratio will be certainly out and cause the engine to stal