Distributor rotor keeps burning out Chevy Astro 1996?

A couple of months ago our van started loosing power, especially when going up hill. Sounded as if it was misfiring. Took it to a dealership and they couldn’t find anything. a couple of weeks later it was getting worse then died on us. Back at the dealership they found the distributor rotor was burnt out. She was running fine for a few days then the "chugging" and loss of power started again though not as badly, also a really strong smell of gas. We drove her 2000km home (we were on holiday at the time) and she really struggled. Haven’t driven her much since we got back, took her out Friday and she died again. Had her towed to the local shop but they have never worked on a Chevy before, they said the rotor has burned out again and we should replace the rotor and the cap but asked us to find out if there is a known reason for this to happen on Chevy’s? Also there is still a strong smell of gas.
Any suggestions would be appreciated.
Thanks