I remember a post some time back that described "retraining the Cruise" it was a detious task of getting it to a speed that was (say 60) safe on a clear, straight, level roadway and setting the cruise, turn it off while holding the pedal and speed @ 60 then back on and set again. You had to repeat this process like 10 times or something crazy like that. If didn't work on my 99 - I replaced the vacuum actuator assy under the drivers battery and all has been well for like 4 years and 60k miles. The actuateor wasn't too bad a job to replace, owrst part was removing the battery and it cost (back then) about $70. 00 from the dealer - pretty cheap for a dealer part for our trucks. Search a bit here and see if you can find the re-train post or maybe someone with a less failing memory than I can remember the exacts. $70. 00 + 1 hour and success = priceless.