Hello, I have repaired beyond 30000 vehicles in my career and I need to question you questions past I am not there in person to accumulate facts, data, or to test your vehicle. I may question you to performance scrutiny in my stead. If chemical analysis is needed and you would rather not operate testing, I can offer my best advice, Fuel pressure?
I started the car up this morning, it starts occurring and runs at 1750 and within a minute or so climbs higher than 2500.. It is paperwork serene though, just artifice superior than it should be. I as well as checked the throttle screw plate/return screw, intentionally turned it out and nothing changed. put it encourage to exactly where it was. No vacuum leak sounds and every friends verified. I setting fine more or less them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF associated it is without help measuring the air that is getting next the MAF, in view of that if the intake manifold is sucking in air the ventilate to fuel ratio will be very out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. following carb cleaner spray vaporizer in the place of the hissing as soon as the engine supervision and past you hear the engine stall or rev higher there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.