I had a 99 Sport that did that while still under warranty with about 20k on it. The Jeep dealer said that was a common problem on 1999 models, something to do with a connection behind the instrument cluster. They fixed it in just a few minutes, and it never did it again while I owned it. My 2000 has never had that problem. If no one on here can answer your question better, maybe you could ask a Jeep dealer that has been in business since 1999.