my mercedes-benz looses power when the ESP code pops up.

Electronic Stability Program - ESP - identifies driving situations approaching critical road-holding limits such as evasive manoeuvres and helps the driver to stabilize the vehicle by braking individual wheels and adjusting the engine output accordingly. So there is nothing wrong with the ESP. The computer shuts it down automatically when the engine is not running right, just like a Lexus. It does not want the throttle and brakes trying to stabilize the car when there is something wrong with engine.. That can be even more dangerous Get an OBDII scan at a parts store (if you feel like messing with it. Or just take to dealer) but if you get a scan bring the codes back here and post them. They will be PXXXX