if you could get the obd 2 code for the cruise it would be very helpful. call the store you took it to and if by any chance they can check their scan tool for history codes and tell you over the phone. i would then check the fuse to the cruise. check if there are any crack in the vacuum line to the cruise unit. a faulty vss (vehicle speed sensor) will also cause it to malfunction. there are alot of tsb bulletins on faulty vss for your year.
if any info was helpful please thank me. trying to build my thanks to get off newbie status.