AFAIK, multiple inquires of the same 'type' within 14 days are classified as one inquiry on your report. This 14 days is considered an average shopping period. However dependent upon who pulls your credit, after the auto purchase, they may look at 45 days as opposed to 14 days.
You must also realize that if you are looking for an auto or a mortgage loan, the credit score will automatically not account for any of the same 'type' inquiries within the past 30 days. What this means to you, is that, any inquiries made in that 30 day period won't affect your score, which is used to determine your rate, so long as the loan is obtained in those 30 days. After that, the two rules apply above as far as the counting of the inquiries.