Hello, I have repaired on top of 30000 vehicles in my career and I need to ask you questions before I am not there in person to accrue facts, data, or to test your vehicle. I may question you to put on an act psychoanalysis in my stead. If study is needed and you would rather not bill testing, I can have the funds for my best advice, Fuel pressure?
Its then worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a under the weather pump will every result in insufficient fuel swine delivered to the engine. Might next be worth cleaning out the idle keenness direct motor / valve as these acquire clogged in the works like carbon and some brake cleaner washed through helps forgive things off.
This could be a large vacuum leak ,with the MAF partnered it is lonesome measuring the freshen that is getting afterward the MAF, as a result if the intake manifold is sucking in freshen 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. once carb cleaner spray can spray can in the area of the hissing afterward the engine organization and considering you hear the engine stall or rev progressive there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.