Figure I might as well post in here maybe someone local can help me out with it.

I have a 1990 f250 460 auto. When I set my cruise on the highway it holds it speed but it keeps speeding up and slowing down but it stays within +/- 2 miles. Not sure where to start looking.

any ideas???

 

My 85 f250 460 does the same thing, never thought about fixing it, I just deal with it.

 

Don't know if those systems use vacuum like the old systems or not... i would start by looking for leaks... just my 2c.