Hi, I have noticed that when I cut off the the throttle when changing gear the engine gains 2 to 500 revs before dropping, this happens when you change gear at either low or high revs, is this normal on turbo Subaru's or could it be as I've been told a sticking idle air control valve, if it is a sticking iacv can these be cleaned or is it a replacement job, I would appreciate any advice on this and thanks in advance, Andy.

Mine does this too... not all the time tho, never really thot of it as being an issue! Will be interesting to know the outcome of this :D

Depends. The iacv should be better after a clean but if not there's not a lot you can do other than replace it

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mine was doing this the other week, took off the IACV and cleaned it, bought a new gasket though as it's near impossible to remove without it breaking.... all working as normal again now :)

Easy way to clean the IAC is to remove it and give it a good clean with Carb cleaner (and an OLD toothbrush), t'will get rid od a lot of the carbon deposits and allow things to work as they should, it's always good practice to replace with new any gasket removed, make sure it's all dry in the IAC prior to re installation, and all should be Robert Your Mothers Brother ;), report back with progress to give feedback to others in a similar situation :D

Mine also did this, seems to have stopped now, I have a bailey dump valve and it sometimes needs greasing up so make sure it closes up quick enough.

think it could do with a stronger spring. 

Also have a look at the butterfly which the throttle cable goes to, mine was sticking and causing it to rev between gears and sometimes on idle. Simple WD spray and a clean up. Mystery_Machine your car looks outstanding.

Thanks Classicscoob2000 :)

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