Check the hose clips for tightness and inspect the trunking for any cracks or splits and moreover every the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best artifice to locate a leak is to have the engine giving out and warm and subsequently vaporizer lighter gas /propane or brake cleaner almost 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 outcome in insufficient fuel visceral delivered to the engine. Might afterward be worth cleaning out the idle rapidity govern motor / valve as these acquire clogged going on afterward carbon and some brake cleaner washed through helps pardon things off.
This could be a large vacuum leak ,with the MAF connected it is by yourself measuring the ventilate that is getting once the MAF, thus if the intake manifold is sucking in air the ventilate to fuel ratio will be certainly out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. when carb cleaner spray can vaporizer in the place of the hissing when the engine direction and considering you listen the engine stall or rev unconventional there is the leak ,could be a bad vacuum hose bad gasket on the manifold.