Check the hose clips for tightness and examine the trunking for any cracks or splits and furthermore all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best showing off to find a leak is to have the engine paperwork and warm and after that spray can lighter gas /propane or brake cleaner in the region of each joint in turn. If the engine rev s taking place you ve found your leak.
Might with be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can reach a quick irregularity locate if you unplug the meter and control the engine without it. if the engine condition is the same subsequently chances are the meter or the relationship to it is faulty. Its along with worth cleaning the MAF sensor wires, as they can get coated considering dirt exceeding epoch which then offsets the reading. Use some log on cleaner or brake cleaner to spray can onto the wires to remove the dirt upon no account touch the wires as soon as anything as they are very fragile
This could be a large vacuum leak ,with the MAF linked it is by yourself measuring the let breathe that is getting with the MAF, thus if the intake manifold is sucking in let breathe the freshen to fuel ratio will be definitely 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 vaporizer spray in the place of the hissing when the engine organization and like you listen the engine stall or rev unconventional there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.