My cruise control is having what I think is a pretty common problem..I have a 91 s10 blazer 4x4 4.3...The cruise controll works fine but slowly losses its "hold" especially when driving up a hill on the highway.It will not hold a constant speed on any type of a grade...It slows down considerably..and will not down shifton a hill.(with the cruise on).I am assuming it is a vacume problem..but I am willing to bet that some one out there had the same problem and fixed it qutie easily...I am about to just replace every vacume hose related to the cruise..Please let me know any suggestions..Thanks alot... Andy