This could be an airleak after the airflow meter, any expose dragged in here isn t seen by the ECU and consequently not compensated for and can lean the engine out and can with allow the engine to rev taking place taking into account not desired causing argumentative running. As its a mechanical deviation it tends not to slant on the deviation lighthearted and you can sometimes hear a hissing noise as soon as 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 under the weather pump will every upshot in insufficient fuel brute delivered to the engine. Might then be worth cleaning out the idle eagerness manage motor / valve as these get clogged in the works taking into consideration carbon and some brake cleaner washed through helps free things off.
This could be a large vacuum leak ,with the MAF similar it is only measuring the air that is getting gone the MAF, hence if the intake manifold is sucking in let breathe 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. subsequently carb cleaner spray can spray in the place of the hissing when the engine running and in imitation of you hear the engine stall or rev difficult there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.