I have a 2000 GMC Sierra 1500 4wd that someone tried to steal a few years back. Since this near theft, issues with the truck have arisen. The most anoying of these is the fact that is only driveable with the lights on. After i turn the key on the dash and radio will turn on like normal, but if i try to start it, it will stumble and die right away. WHen i flip the lights on a few seconds after the beeps will happen saying that its on, and the fuel pump engages. Then its startable. Anyone have an idea as to why this may be happening and what can be done?