i now have have a 1992 940 turbo volvo as a everyday car since myvw jolf is in storage,one little issue i have is that the the idle is too high, when in park and neutralall drive gears idle is fineand on cold start up the idle is normal but once warmed up the idle raises
what could cause this?

 

Bad ECT could cause it,Bad intake manifold gasket,Dirty inproperly adjusted throttle body.

 

what is a ect?

 

Electronic coolant temp sensor.