High idle on hot start?

[Dark_Seraph]

Hey all!

I've just joined the ranks of the priviliged after buying a 1986 8v GTi, but i've only had it a month, so please excuse me if this is a noob question!

Basically, whenever I cold-start the car it idles fine, but if I turn the engine off and then back on again within about 10mins, it idles at around 2000 until the oil reaches 80deg or so. The oil temperature gauge is a bit dicky and quite often does'nt work, could this be related?
The car is stock other than a Pipercross air filter.

Any ideas?

Thanks!

[Dark_Seraph]

Oooop, I meant 1989, hehe. 

[rubjonny]

check out the idle switch, replace the blue temp sender, and tune it as per my digifant FAQ