This could be an airleak after the airflow meter, any let breathe dragged in here isn t seen by the ECU and so not compensated for and can thin the engine out and can next allow the engine to rev occurring in imitation of not desired causing rough running. As its a mechanical aberration it tends not to approach upon the aberration blithe and you can sometimes hear a hissing noise subsequent to the engine running.
Its next worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a ill pump will every repercussion in insufficient fuel bodily delivered to the engine. Might as well as be worth cleaning out the idle speed run motor / valve as these get clogged taking place following carbon and some brake cleaner washed through helps release things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you up 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 going on and is warmed up? oftentimes in engine work many factors may cause the same symptom(s)