1999 Mercedes E300D: Persistent P0725 Code - Engine Surges at 2K RPM After Acceleration

Dear community, I'm seeking help with a recurring issue on my 1999 Mercedes-Benz E300D. The car starts intermittently only after rapid acceleration and fully depressing the accelerator pedal multiple times (two to three attempts). Once started, it runs smoothly at high RPMs, but as soon as I slightly release the pedal, the engine surges sharply to around 2,000 RPM — there is no idle behavior at all. I've already replaced the engine speed sensor twice, inspected and cleaned the wiring harness and connectors, replaced transmission 13-pin plug O-rings, checked oil levels, and performed a full visual inspection of the wiring. I've also scanned the vehicle multiple times and cleared the P0725 code — however, it reappears every time I attempt to start the car. Given this behavior, is the next logical step to replace the transmission speed sensor? Any other diagnostics or troubleshooting tips would be greatly appreciated.