My 1996 Mercedes C280 will occassionally lose acceleration, pick back up, and lose it again
Unfortunately, my mechanic cannot reproduce the problem. I will be driving at normal speed. I stop for a stop sign or light, and when I accelerate it tops out at maybe 20 mph and then slows down to 5-10 mph, speeds ups to 20 mph, etc. The accelerator is held at a constant depression. If I put the car in Neutral, the engine cycles through the same loss and pickup of power. If I stop the car, and let it sit for a few minutes, it typically does not reoccur on that trip. It is not easily repeatable, but the 3-times it has happend to me seem to have the same pattern: I drive the car for about 30', I park for about 15' (i.e., the engine is still warm), I start driving again and it occurs. I have had several refills between incidents so I don't think it is bad fuel. My mechanic's only guess is the fuel pump, but they are hesitant to replace it without knowing for sure due to the expense. I am trying to get the problem to occur again so that I can drive it (slowly!) to the mechanic to experience it first hand. Thanks for any ideas.
