My 75 450SL exhibits following idle behavior:

With warm or cold engine,

When in neutral or park, idles at about 1000 rpms

when in drive, stopped at a light, it idles at 700-800 which I believe is normal based on the metal tag at the front of the engnie compartment. If I shift it to neutral, the idle speed immediately climbs back around 1000 rpm.

is the car idling too high while in neutral or too low while in Drive and stopped at a light?

thanks in advance

dom

Pics of my 1975 450SL