sounds like a simple suggesting but have you run the car with the iscv unplugged? i cleaned mine out and tried everything else only to find the actual unit was knackered. i just drive round with it unplugged for now till i fit the new one i got
that is going to be my next point of call
should there be any difference in the sound of the engine when you unplug this ie should it drop revs etc..?
i have got a brand new one that i am waiting to buy