mk2 2l 8v gti rev prob

have a strange problem with my mk2 2l 8v gti, when i hold the throttle open in neutral gently so it rises slowly to about 2200 rpm every now and again it falls back down to idle then builds back up even though my foot doesnt move, im thinking throttle swiches on top of the inlet manifold, thoughts please

 

^What he said^ ....more likely ISV

Soak it in paraffin for 24 hrs and see if that helps.

 

NNNNNNNNOOOOOOOOOOOOOO!!!!! Don't waste vodka on it!!

 

or maybe its the idle air valve fogive me if this has already been told im new here trottle body cleaner will prop be the best thing to clean with