hi all,

i hve a subaru sti type r.version 5.

recently it has become really lumpy on idle and running rich.like im sitting on a washing machine.lol

I have pressure checked the valves,changed the plugs and the leads,and the distributer or coil pack(wot ever its called).

recent diagnotic only shows the knock sensor as being faulty even after a ecu reset.

i believe the fault to has something to do with a loss of air at some point.the previous owner fitted a hks dump valve.however the car has been runing fine up until recently.i cannot find ne1 to take it to,to fix the problem.So far every one i have been to believes the car is running fine.but i know better..i am based in birmingham.

p.s..on some days the the cars starts like as if its got a cold.it ticks over very faintly and for longer than usual.however once i get it going i simply rev it once and its bck to normal..wots that all about?

can any1 help me.