Hi you guys,
had a 98 GC 3.3 doing the same thing, turned out to be the inst cluster connector resolder, i took some pics during the process and my wife let me put them on her site
www.ingriddijkers.com - go to the "links" page - scroll down near the bottom on the right side you will see "caravan pics" hope it helps you, many of us have had the same problem.
when you inspect the solder joints they will look fine but the connections are more like solder bubbles than good joints.
i know first hand how frustrating this problem is! the dash bang will get you going though until you have time for the final fix
best of luck
keep in touch,
Bob