Originally Posted by carsavvycook
If the intake gasket is not sealed right, and is sucking oil into the #2 port, by spraying carb spray into the valve cover, which is into the crankcase, your idle will increase, as the intake sucks it in through the leaking gasket.
makes sense. Should I let the car reach normal operating temp before doing this? Or can it be done as soon as I start the car ?