HOLY CRAP, I just put a Dr performance box on an 02 cummins, and now it has the same issue. So far ive done this: removed chip, checked all connections, wires and grounds i could get my hands on, swapped PCM and Cluster from another truck, put battery charger on to make sure there's proper voltage. and today i started checking Power and grounds at the 2 connectors for the cluster. All powers and grounds seem to be good.