W-2 Employee. Receive $600/mo car allowance. Also company gas card. Car allowance is taxed, card isn't. Is there any additional deduction I can take for mileage?

I don't get taxed on the amount of gas I spend for my vehicle.  It is reported on my pay stub but later deducted and not taxed.  Also I purchased a truck specifically for work because it was suggest this would be the best vehicle to use.  Can I take any deductions on it?