power loss but engine stays on, then brakes are spongy

Hello, definitely an odd deal that requires hands on diagnostic testing. I can't be certain that the brake issue and the engine power issue are related to each other. You do have an electronic throttle body with no cable from the accelerator pedal, rather sensors operating the throttle control. It would be a good idea to have this system tested, see if any diagnostic trouble codes (DTC's) are set in the engine's processor, looking for clues.