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:
Fixed passenger seat
Adjusting the reclining seat back
Lift lever A-fig. 52.
...
Looking after the system
During the winter, the climate control system must be turned on at least once
a month for about ten minutes. Before summer, have the system checked at a Fiat
Dealership. ...
LATCH — Child Seat Anchorage System (LowerAnchors and Tether for CHildren)
Your vehicle is equipped with the child restraint anchorage system called LATCH,
which stands for Lower Anchors and Tether for CHildren. The LATCH system provides
for the installation of the child ...