Wilsons Sandbox

Hello, Yesterday, on I 40, while running 65-70mph i noticed a slight miss. It would cause my head to go forward a couple of inches and it would do it ever minute or so. It had me worried a bit, but it did not get worse. It only did it while on the Intersate, which was about 100 miles. There was a head wind, with gusts, most of the time, but I'm certain there was a miss. I could give it throttle (more rpm's) and it would not miss. It was at the cruise speed that it did it. When I got off I 40 it ran perfectly the remaining 60 miles of hills and curves. The bike has over 8k miles on it with out anything being done to it. I have noticed that it pings or knocks like it may have some water in it or like it needs higher octain. Oh, i did clean the filter recently and oiled it properly with the sticky oil. Any ideas as to what the problem is. I know it is time to check the valves, but if that was all it was then wouldn't it miss at higher rpm's? Robert Waters [Non-text portions of this message have been removed]