Is it a early Sidekick Tracker?
Most Likely you need the computer fixed from the faulty capacitors
used in their manufacture, they leak and corrode the traces that
makes the trucklet run.
There are several places that can fix them, or if you are a computer
savvy kind of person you can fix it yourself.
The computer is high up under the dash about where your right knee
is, it's the gold color metal box, so give it a go or get it pulled to be fixxed
Good Luck
Wild