Here’s one for you. I have a 1987 300E with 145,000 miles that I have owned for ten years. When the car was almost new, every once in while, usually during the summer, the RPM would surge and the car would buck. This happened maybe once twice a year and then went away. Over the years it began to occur more frequently and today it does it almost every time you run it. One day it will run like a top the next day it will hardly start constantly surges in park, and buck and surges when you drive it regardless of the speed and RPM. Worst of all sometimes in the middle of a turn at an intersection it just dies. It has never however failed to NOT start again??? I have it to four MB dealers all over the country and at least that many Foreign Auto shops and no one can seem to find the problem. We had hoped for a hard failure of some sort but no luck. I spoke with the original owner and explained the problem and he told me when the car was brand new it did this a couple of times. Anyone have any ideas? On the days it runs, the engine purrs like a brand new car.