It is very unusual to make a profit on the sale of a personal vehicle. You would have to sell it for more than you paid for it, to include any major repairs (incl. tires) made in the time period leading up to the sale.
If you did make profit, you'd report it on your tax return using the "Stocks, Bonds, Mutual Funds and Other" interview of "Investment Income" ( a personal auto would be "Other").
