Why does 450SL run poorly when plug from the throttle body is not connected?

The 450SL runs poorly when the throttle body plug is not connected because this plug typically supplies essential signals for fuel injection and air intake management. Without this connection, the engine may not receive the correct amount of fuel or air, leading to poor performance, rough idling, and potential stalling. Additionally, the engine control unit (ECU) may not function properly without the necessary feedback from the throttle body, further exacerbating performance issues.