[x3Prancer]

After starting the engine, should we wait for the idle to go down?

Even if the engine is started again after being turned off and warmed up already, the idle still runs around 1200 rpm for around half a minute before lowering to around 800 rpm. And, during the time that the idle is running fast, the engine is making more valve noises, slowly decreasing volume, until it goes away, then the idle licks down to 800 rpm. Is there something going on during this fast idle, like oil pressure building up, or something getting lubricated, that I should wait for? Or is it ok to drive off while it is still idling high?

[kscarrol]

Warming up the catalytic converters so more of an emissions thing than warming up the engine etc. You’re fine to drive off…

[Piki]

Just drive, idling on cold engine is bad idea. The quicker it get to temerature the better.

[Flippco]

My preference is waiting until the first engine kick-down but that's just because I'm that old guy now. As others have stated it is perfectly fine to start and drive. Modern engines and fluids have been improved so that you don't need an excessive warm-up time.