1987 560SEL High Idle & Anitlock Brake Light On
I have a 1987 560SEL. After about 15-20 minutes the engine idle will jump to about 2000 rpm and the antilock brake light will come on. It can happen during driving or when at a stop. It will usually endure for about 5 minutes and then return to normal idle and the light will go out. It may occur more than once during a drive and seems to becoming more frequent.
Also, when the idle speed has returned to normal, the car will "surge" when I am coasting down hill with my foot off the accelerator. Feels like someone holding the car and then letting go repeatedly. If the accelerator is depressed by the slightest amount, the "surge" will stop.