2001 Mercedes Benz 320e no acceleration when pressing the g

There are a few things to consider. First a failed throttle position sensor. When these fail you will loose throttle response. Often times you will experience disproportionate acceleration according to pedal position, also the sensors at times will flaten out causing dead spots in the throttle pedal. Also a worn diaphragm in the fuel pressure regulator may cause a problem similar to this. Also, depending on the quality of gas you use this may also be a plugged fuel filter. Cheap gas does not react well with MB parts. Tell me, do you have any warning lights on in the dash. Is there any bucking or jerking that is associated with the problem? How is your fuel mileage? Lower than normal?

This definately sounds like a failed throttle position sensor or throttle actuator. More than likely the beginning of the end of this sensor or acutuator. I would definately recommend considering these as a very possible cause for this. Often times this will not throw a warning light either but replacement of these over time is fairly common for conditions such as yours.