I gad a similar instance about 7yrs ago. Cruising along at about 70 and it felt like I hit something, only I didtn't hit a huge pothole(non in teh road), and nothing large ran out in front of me. The CEL popped on and themn went off, no code was stored. It was comming due for a valve adjustment so I took it into he dealer, mentioned the problem, got no response, but they dealer found a burnt exhaust valve when they went to do teh adjustment.

The other instance I had with a loss of power like that, was with the speed sensor. Everything would shut down, but it never turned off.