This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and for that reason not compensated for and can thin the engine out and can then allow the engine to rev happening next not desired causing scratchy running. As its a mechanical idiosyncrasy it tends not to incline upon the deformity vivacious and you can sometimes hear a hissing noise once the engine running.
Thanks for your response. I just checked what you mentioned, that I hadn't already checked, except fuel pressure.Let me tell you a little more more or less the hardship history. It currently has a master tech endorsed idle ventilate run valve and tps installed. without touching anything, the last (used) ecu and my original, would rule in the car without this symptom.
This could be a large vacuum leak ,with the MAF associated it is only measuring the expose that is getting in the same way as the MAF, consequently if the intake manifold is sucking in ventilate the let breathe 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. taking into consideration carb cleaner spray can vaporizer in the place of the hissing past the engine dispensation and when you listen the engine stall or rev vanguard there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.