I recently purchased a Trek Super Commuter 8s with the Bosch Performance motor. I live in a very hilly area and I've been riding it every day. No problems at all, very natural feel. Today I tried a much stepper hill and ended up in the lowest gear on the cassette and in Turbo on the motor. I currently have 125 miles on the bike. At first it was fine but it started surging. I wasn't able to maintain a steady cadence, and if I paused in pedaling, the motor would continue to pull. Then, when I would begin pedaling again, the motor would lag initially before surging again. Once I cleared the hill, it continued this behavior in a number of gear and motor combinations. I immediately took it to my dealer and they said they put it through a diagnostic test. It showed no errors. It feels, to me, like an issue with the pedal sensor.