[lady-turbo-wrx]

Hiya
heres my problem,my scoobs going realy well (at the moment) only for the last week or so,i have had erratic idling,but only when i put my foot down..
if i drive say normaly,it idles around 1200 but if i put my foot down hard,its idling between 2000-2500 but if i put the clutch down and rev a few times comes back generaly to 1200,or just driving the scoob normaly does it too,have tried WD40 on the throttle cable,but still not fixed it,only thought was an idle sencor

Any thoughts on this please...trace..x