This is just an idea. I hope you can follow what I am saying. I know I didn't do the best job of putting it into words.
Could it be that your cruise is kicking in and out because of speed? Are you right at the set point of the cruise?
Say you have your cruise set for 60mph. When you start going down the hill your car speeds up to 63mph. The cruise backs off of the gas and you slow down, say to 58mph. Your cruise then kicks in again and speeds you back up, past 60mph and then slows down. Could that be the problem, or am I totally off base?
My old 98 Tour would do that. It was a 2.0 ATX though.
