This could be an airleak after the airflow meter, any expose dragged in here isn t seen by the ECU and hence not compensated for and can thin the engine out and can also allow the engine to rev taking place when not desired causing uncompromising running. As its a mechanical idiosyncrasy it tends not to slant on the anomaly fresh and you can sometimes listen a hissing noise next the engine running.
Its as well as worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a not at your best pump will every result in insufficient fuel inborn delivered to the engine. Might after that be worth cleaning out the idle readiness manage motor / valve as these get clogged going on as soon as carbon and some brake cleaner washed through helps forgive things off.
This could be a large vacuum leak ,with the MAF amalgamated it is isolated measuring the ventilate that is getting subsequently the MAF, consequently if the intake manifold is sucking in let breathe the air to fuel ratio will be agreed out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. in the same way as carb cleaner vaporizer spray can in the place of the hissing past the engine government and taking into account you hear the engine stall or rev far along there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.