It depends. First, you must itemize to do so. Then, you must choose to deduct state and local sales tax rather than state and local income taxes. If you make this choice, you can add the sales tax on the car to the amount of sales tax that the IRS allows for your household size and income.
A business method of accounting requiring income to be reported when earned and expenses to be deducted when incurred. However, deductions generally may not be claimed until economic performance has occurred.