Check the hose clips for tightness and inspect the trunking for any cracks or splits and in addition to every the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best pretension to locate a leak is to have the engine giving out and warm and subsequently spray lighter gas /propane or brake cleaner with reference to each joint in turn. If the engine rev s going on you ve found your leak.
Might in addition to be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can accomplish a fast irregularity find if you unplug the meter and manage the engine without it. if the engine condition is the thesame after that chances are the meter or the membership to it is faulty. Its afterward worth cleaning the MAF sensor wires, as they can acquire coated taking into account dirt on top of era which next offsets the reading. Use some gain access to cleaner or brake cleaner to spray onto the wires to surgically remove the dirt upon no account be next to the wires later everything as they are agreed fragile
This could be a large vacuum leak ,with the MAF united it is and no-one else measuring the let breathe that is getting behind the MAF, so if the intake manifold is sucking in let breathe the let breathe 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. past carb cleaner spray spray in the place of the hissing once the engine handing out and behind you hear the engine stall or rev difficult there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.