All gasoline sold in the United States is required to contain effective detergent additives. Use of additional detergents or other additives is not needed under normal conditions and would result in additional cost. Therefore you should not have to add anything to the fuel.
See also:
If the battery is flat
First of all, read the “Vehicle maintenance” section for the steps to be taken
to avoid the battery running down and to ensure it has a long life.
IF THE BATTERY IS FLAT
Charging should be slow at ...
Key-In-Ignition Reminder
Opening the driver’s door when the key is in the ignition and the ignition switch
position is OFF/LOCK, sounds a signal to remove the key. ...
Engine
...