i stuck somenew plugs in it today focus rs 2.5l, they came gapped and were checked anyway, made no difference in running o the car, also the head was completely re-built ported and polished before i was removed from the bay, it had only covered 600 miles until a piston failed and was stored as it came off with all manifolds still intact,

the car idles well and doesnt smoke etc, seems to rev up freeish apart from a bit of a glitch around the 2000 to 3000 rpm window, sometimes when on idle and i press the accelerator the car bogs out then revs rise and then hesitate againg at around 2500 ish rpm, took it out for a spin today and the tap does not get louder with rpm, when on boost pulls lovely, currently on low boost 7 psi,

parts changed today to try and rectify problem,
spark plugs
coil pack
edis module-back o original now as it made no difference
fluid levels checked
timing checked with dal gauge and cams lock when cylinder 1 hits tdc.

the batter is fine it has enough cranking voltage and the car starts o the key idles well with iscv connected, an sits smoothly at about 800-900 rpm when disconnected, doesnt hunt or race on idle