no acceleration 1990 300SE
 

the car stopped accelerating, couldnt go over 60 MPH,had cold start problems, idle problems, the gas pedal broke. two shops could not diagnose problem. They adjusted linkage. Car ran worse then before their repair. Said all diagnostics indicated no faults, everything good with sensors. I replaced rotor and distributor cap which fell apart in my hand, One year old. Replaced battery. Replaced Idle control Valve. Finally took vehicle to MB dealer, they replaced OVP relay. IT's running a lot better, a little more power. My ABS now working, no cold start problems but idle still intermittantly surging and the car is still a dog. It has no pickup, it does not kick down when accelerating, takes about 1/2 day with gas pedal to floor to reach maximum speed of 60-70 MPH. My leg is cramping from effort to hold gas pedal to floor. Engine compression checked and it is fine. I do not want to junk my baby but I have really had it. any comments or what I should do next would really be appreciated.

I would let the dealer try and diagnose the problem. It sounds a lot like the engine is not getting proper fuel...perhaps a fuel pump issue?

I would suspect a vacuum leak if the trans will not downshift - the surging might be related?