started my RS up today and it idles at about 2k, what would be the cause of this?

I've been told the idle speed cannot be adjusted manually so its moer than likely a sensor gone wrong, probably the ISCV clogged up?

Any input would be great, thanks

 

soak it in some petrol, see if that cures it

 

just so happens I have a load of petrol sat in a can