W140 surges at low idle
For the past week or so, My 1995 S320 rythmically surges when stopped at a light, or at a slow crawl (stop and go traffic). On the tach it bounces from about 600 to 800 RPM or so, every second or two. You can feel it in the motion of the car if I am moving very slowly.
There doesn't seem to be any noticable affect over about 1000 RPM.
Any thoughts on what might be going on, and what I should check?