380SL high idle after cold start

[Grammabud]

Hi everyone, I am a new member with an old 380SL. It is an 85 with 230K miles. It was a gift, I think. After removing several bushels of pine needles and evicting the ant colony, it seems to be in unmolested condition. With about 30 miles of test running, everything seems to be in OK order.
My initial question is regarding the high idle condition after a cold start. It starts immediatly, (hot or cold) but idles very high (about 3000) when cold. As the engine worms up, the idle gradually reduces to a normal speed. Is this normal? Any advice will be most appreciated.
Many thanks in advance,
Grammabud