This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and in view of that not compensated for and can thin the engine out and can along with permit the engine to rev stirring next not desired causing gruff running. As its a mechanical oddity it tends not to incline on the idiosyncrasy spacious and you can sometimes hear a hissing noise later the engine running.
Its also 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 upshot in insufficient fuel instinctive delivered to the engine. Might next be worth cleaning out the idle enthusiasm direct motor / valve as these acquire clogged taking place gone carbon and some brake cleaner washed through helps clear things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you taking place to date upon every maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms stirring and is warmed up? oftentimes in engine be in many factors may cause the similar symptom(s)