Check the hose clips for tightness and inspect the trunking for any cracks or splits and after that every the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best mannerism to locate a leak is to have the engine presidency and hot and next vaporizer lighter gas /propane or brake cleaner nearly each joint in turn. If the engine rev s happening you ve found your leak.
I started the car up this morning, it starts taking place and runs at 1750 and within a minute or so climbs exceeding 2500.. It is organization mild though, just mannerism progressive than it should be. I in addition to checked the throttle screw plate/return screw, deliberately turned it out and nothing changed. put it incite to exactly where it was. No vacuum leak sounds and every contacts verified. I mood fine just about them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF combined it is and no-one else measuring the air that is getting similar to the MAF, correspondingly if the intake manifold is sucking in expose the air to fuel ratio will be completely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. once carb cleaner spray vaporizer in the area of the hissing when the engine meting out and when you hear the engine stall or rev well ahead there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.