2014 mercedes e350 sedan shaking when accelerating from 1500-2000rpm. When I get to highway speeds from 50-65 when I press on the accelerator it will vibrate and the rpm’s will drop significantly. Also, when I accelerate the rpm’s sometimes drop a little bit for no reason. Anybody know how to fix it? I’ve taken it to a mechanic and they tried almost everything. He’s going to install a torque converter next.

when I go below 40 nothing will happen for the rest of its life. But the moment it goes above 50 it will keep shaking at those specific rpm’s no matter what speed it is.

is it the torque converter, tranny, or is the car bricked?

This is the car in question. 2014 E350