This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and thus not compensated for and can lean the engine out and can afterward allow the engine to rev happening as soon as not desired causing unfriendly running. As its a mechanical aberration it tends not to slant on the defect light and you can sometimes listen a hissing noise past 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 poorly pump will all upshot in insufficient fuel monster delivered to the engine. Might after that be worth cleaning out the idle swiftness govern motor / valve as these get clogged stirring subsequent to carbon and some brake cleaner washed through helps forgive things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you taking place to date upon all maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms up and is warmed up? oftentimes in engine affect many factors may cause the same symptom(s)