Hi, I own a 52 plate Impreza wrx, totally standard, 75k miles.

The problem is when I change gear and cut off the throttle and depress the clutch the revs increase by 200 to 500 revs before dropping, I have heard it could be a sticking ( idle control valve ) or the ( neutral position sensor ), has anybody else experienced this and if so how did you cure it, this is really annoying and I would love to stop it.

Any explanations to why it does this and advice on fixing it will be much appreciated.

Thanks in advance, a fed up wrx drive.

Mine does this, not too bad now after cleaning the IACV. 

First things first, buy a replacement gasket. You can pick them up for a few quid.

Take a picture of the IACV before unscrewing so you can get the screws back in the same position, otherwise it could alter your idle.

Unscrew and unplug the IACV, take some petrol or carb cleaner to the valve and you can let it soak for a while. I used some cotton buds to remove the heavy build up of carbon.

Once it's cleaned and dried, put your gasket on then reattach!

Pretty straight forward :D