Thanks, W126.

Hard to say if smoke is really gray or white. This is difficult. It is not black, more a color in between gray and white.

I have been experiencing increased oil consumption the last few months. Maybe this helps.

Also, I think I seem to detect a sort of not hissing sound, but more of an air sound upon acceleration.

However, temp gauge stays rock solid at 80, or at times, just a tad higher. Even at stop signs or lights. (And I live in Miami).

I idi replace my own plugs (difficult), about 4 months ago, and although engine does not miss, one or two of the plugs I suspect might not be seated properly.

What do you think?