UK Car Repair: corsa, inlet manifold, blockages

Question
hi ive got a 1994 corsa merit 1.2 an ive got a problem with it there is no problem starting up its great but when i go to drive it it wont go proper it sounds like as if someone is chokeing my car an im not gering any power. my air box flap is working it is like my car is not getting enough air or to much does any1 no wot i can do thank

Answer
You say the air box flap is working,  is this the one before the intake? and, is the idle speed normal?  It sounds as if there is a break/leak in the inlet system or else the throttle flap at the inlet manifold is not opening correctly. Presumably, you have checked there are no blockages in the filter housing or before it!