This could be an airleak after the airflow meter, any freshen dragged in here isn t seen by the ECU and for that reason not compensated for and can lean the engine out and can as well as allow the engine to rev up when not desired causing harsh running. As its a mechanical idiosyncrasy it tends not to approach on the fault lighthearted and you can sometimes listen a hissing noise with the engine running.
Thanks for your response. I just checked what you mentioned, that I hadn't already checked, except fuel pressure.Let me tell you a little more about the trouble history. It currently has a master tech recognized idle freshen run valve and tps installed. without distressing anything, the last (used) ecu and my original, would direct in the car without this symptom.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you in the works to date on all maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms taking place and is warmed up? oftentimes in engine behave many factors may cause the thesame symptom(s)