Men are more likely to be car enthusiasts than women. There's no sexist reason for this that I can devise, but this site is full of very smart car enthusiasts.
I also belong to CobaltSS.net, which has similar statistics, but the poll results do show more women on the Cobalt site. The Cobalt is much less masculine than the new Camaro. There are also more idiots on that site because most people there are high schoolers and college students who don't have any respect for their whips.