Hello, I have repaired higher than 30000 vehicles in my career and I craving to ask you questions past I am not there in person to accumulate facts, data, or to exam your vehicle. I may question you to feat chemical analysis in my stead. If breakdown is needed and you would rather not operate testing, I can find the money for my best advice, Fuel pressure?
Might also be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can complete a fast irregularity find if you unplug the meter and direct the engine without it. if the engine condition is the same then chances are the meter or the connection to it is faulty. Its in addition to worth cleaning the MAF sensor wires, as they can get coated in imitation of dirt over period which then offsets the reading. Use some get into cleaner or brake cleaner to spray onto the wires to surgically remove the dirt upon no account touch the wires once anything as they are definitely fragile
This could be a large vacuum leak ,with the MAF linked it is unaccompanied measuring the ventilate that is getting gone the MAF, in view of that if the intake manifold is sucking in air the expose to fuel ratio will be unconditionally out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. next carb cleaner spray spray in the area of the hissing later the engine dispensation and with you listen the engine stall or rev future there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.