This could be an airleak after the airflow meter, any air dragged in here isn t seen by the ECU and suitably not compensated for and can thin the engine out and can as a consequence permit the engine to rev up with not desired causing uncompromising running. As its a mechanical anomaly it tends not to twist upon the defect open and you can sometimes listen a hissing noise bearing in mind the engine running.
Thanks for your response. I just checked what you mentioned, that I hadn't already checked, except fuel pressure.Let me say you a little more very nearly the pain history. It currently has a master tech attributed idle let breathe govern valve and tps installed. without touching anything, the last (used) ecu and my original, would run in the car without this symptom.
I don't have any check engine lights unless I unplug the MAF sensor. considering the MAF is plugged in next the car will stall unless I put my foot upon the accelerator. There is along with an intermittent popping unassailable coming at idle.