You can claim anything that is not reimbursed. If you own the vehicle and they did not reimbursed mileage for instance, then you can claim that as a deduction. Likewise, you cannot claim the gas, as it was paid for by the employer. Work your way through the section and claim what applies to you.
Visit this IRS link for a more complete explanation on how to claim
job-related vehicle mileage and expenses:
https://www.irs.gov/pub/irs-pdf/p463.pdf