I am helping a nonmechanic friend take care of his '85 280 SL (M110 engine). When the car is first started, even in hot weather, it idles at about 1500 rpm for the first 10 minutes or so, then settles down to about 750 or so rpm. The idle is always smooth and steady, it's just high on initial startup. Is this normal in warm weather? It has k-jet fuel injection with lambda control and a catalyst, if this makes a diff.
Thanks for any help!