97 s420 no power with petal to floor and knocking

engine runs but feels like bad missfire at idle. also has a knocking but with my petal to the floor the car doesnt want to move at all i barley get to 20mph. has new coils and plugs and plug wires - connectors. any ideas would be greatly appriciated. thank you

Your car has an electronic throttle body called an ETA. With the car in park remove the hose going to the intake and look at the throttle blades and see if they move while a partner pushed the gas pedal down. If it doesn't then you most likely need to replace your ETA. These are very common problems on 90's Mercs.