Service Tax is certainly payable in your case.
The main theme is that if you are renting the motor vehicle to another person, who is also engaged in similar renting of vehicles, then reverse charge is not applicable and you shall pay the service tax at full rates in respect of the amount charged by the other person.
In other case, if you are providing services by way of renting of motor vehicle to ultimate consumers alone then reverse charge would be applicable. You can also take benefit of abatement as notified vide Notification 10/2014 ST Dt. 11.07.2014.