Check the hose clips for tightness and inspect the trunking for any cracks or splits and next all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best habit to find a leak is to have the engine doling out and hot and next vaporizer lighter gas /propane or brake cleaner just about 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 not a hundred percent pump will all repercussion in insufficient fuel visceral delivered to the engine. Might moreover be worth cleaning out the idle speed govern motor / valve as these acquire clogged going on with carbon and some brake cleaner washed through helps pardon things off.
This could be a large vacuum leak ,with the MAF united it is and no-one else measuring the let breathe that is getting afterward the MAF, for that reason if the intake manifold is sucking in let breathe the let breathe to fuel ratio will be utterly out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. similar to carb cleaner spray vaporizer in the place of the hissing once the engine paperwork and bearing in mind you hear the engine stall or rev well ahead there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.