here was the situation...we were on an empty freeway the other day and it was raining and windy...the route was 50 miles, and autopilot worked fine the majority of the way. then all of a sudden, autopilot went from 65 mph to 30 mph and stayed there...was pretty alarming. the speed limit didnt change, as i was on a freeway. we kept going and turned AP back on, and it happened again a minute or so later. i suspect something must have blocked one of the sensors, but didnt seem that likely as the whole trip was raining. on the second time, i didnt do anything and wanted to observe if the speed would crawl back up (freeway was pretty empty), but it stayed around 30-35mph, and then eventually cars caught up and i had to drive faster. AP worked fine the rest of the trip....any ideas as to what is going on?