V reg 1.2 idle problem when hot

slater boy4 · Post by **slater boy4** » Thu Mar 15, 2012 4:24 pm

Hi,
I own a v reg 1.2 16v that has an idle problem when hot. It will cold start ok and although not perfect will idle OK albeit revving a bit until it settles down. You can witness the idle valve moving in & out whilst doing this.
When warm after say motorway driving it will then rev and maintain high revs at a roundabouts/traffic and do your head in! On changing gear it will maintain high revs too.
I have read threads that say crankshaft sensor but would that not effect it when its cold too? The idle control valve does move again when its hot and doing this which also confuses me as I thought this would be for only cold starting?
It drives fine so I have lived with it up to now although I have replaced the complete throttle body inclusive of sensor & idle control (scrap part) as well as the mass air flow (brand new) to no avail.......what next?
Any ideas?