Welcome Bruce,
While I've never sold cars I do a lot of cold calling and I suspect it's not going to be much different.
The best cold calling scripts I've come across are those by Jacques Werth who frequents this board from time to time. He's created what he calls "High Probability Selling" and the formula should work perfectly for what you want to accomplish.
In fact, some of the results I've seen published might suggest that you could become very wealthy in a very short period of time this way.
Good Luck,
Chuck