This could be an airleak after the airflow meter, any air dragged in here isn t seen by the ECU and correspondingly not compensated for and can thin the engine out and can along with permit the engine to rev up behind not desired causing brusque running. As its a mechanical deformity it tends not to perspective on the fault spacious and you can sometimes hear 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 tiny more nearly the burden history. It currently has a master tech endorsed idle let breathe govern valve and tps installed. without touching anything, the last (used) ecu and my original, would rule in the car without this symptom.
I don't have any check engine lights unless I unplug the MAF sensor. taking into account the MAF is plugged in then the car will stall unless I put my foot upon the accelerator. There is then an intermittent popping hermetic coming at idle.