Obviously I've never bought a car, but someone on the Dave Ramsey board posted a few years ago about an experience she had as a woman buying a car. She had been admiring a truck on the lot, and finally went during business hours to check it out. The salesman took forever to even acknowledge her, gave her shrugs, I-don't-knows and half-answers to her questions, refused to look up something on the computer for her, tossed her the keys when she asked for a test drive and then took forever to acknowledge her again when she came back. She told her brother about it and they went back together the next day. She stayed in the car. He got out. The SAME salesman walked right up to him, gave complete answers to all of the same questions she had asked, even offered to knock $1000 off the price. When he asked if he was ready to do the deal, he was shocked when the brother declined, pointed out his sister sitting in the car and said "Why couldn't you tell HER all that yesterday?" Then he got in the car and drove off.
And my mom said when her dad took her to buy her first car, he had to keep telling the salesman to ask her, talk to her, she's buying the car, not him.
There's most definitely sexism involved in car sales.