I just got my aftermarket (i.e., junkyard) cruise control working. Had to replace two of the small vacuum tubes running above the intake. I probably have some other small vacuum leaks in more difficult locations. Even so, the cruise works pretty well on the highway, much better than my right foot, but the speed still varies +/- 3mph from what I set it at. I usually lose a little speed going down hill, then regain it going up. Since this is my only experience with the Volvo cruise control that uses engine vacuum (rather than an electric vac pump), I don't know whether this is as good as I can expect, or if I can get a steadier speed with more troubleshooting for vacuum leaks. I also have a '90 760 Turbo and a '96 960, both with cruise, and their speed on the highway hardly moves even 1 mph, uphill or down. Any comments would be appreciated. Thanks.