if you are saying no taxes are taken out of your paycheck (They pay full amount no taxes taken out). in this case the employer is treating you as an independent contractor. you will file a schedule C where you can deduct your actual vehicle expenses net of the reimbursement.
if you were an employee you would have gotten a w-2. in a non accountable plan the reimbursement should be included in you W-2 wages box 1 for which you get no offsetting deduction whereas under an accountable plan it would not be included on the w-2 and you don't need to report it.
