ph2 172 idling very high

[lesley]

Anyone got any ideas as to what it could be?

It jumps around when you stop then creeps up to about 2500 revs and stays there. I have lots of driving to do today so need to fix it today

 

[MicKPM]

Sounds like an air leak to me. Has anything been done to it recently?

 

[d19wood]

I cranked the two torx head bolts down at the front of the engine cover too much and this was enough to create a leak by breaking the seal between the gasket and intake manifold this had the effect that you describe on mine. Slackened them off a bit and problem solved but was a head scratcher for a bit.