When you say you topped it off, did you top, top it off like all the way up to the brim? Is the odor stronger in the trunk than in the cabin? Only thing I can think of would be that with the warm weather we had, the gas perhaps expanded enough to force vapors into the trunk and with the top up, into the cabin. Try opening it up and letting it air out. Make sure you prop something so the top doesn't come down as it will after 10 minutes or so. Wish I could be more help.

Take care