If they appear damaged or deteriorated, replace them.

Balancer Adjustment
Torque LimiterStick Coil Removal
Remove the air cleaner housing (see Air Cleaner Housing
Removal in the Fuel System (DFI) chapter).
Disconnect the stick coil connectors [A].
Pull out the stick coils [B] upward.
First, turn the stick coil by 90 degrees, and then pull it out
by twisting the coil head to the left and righ ...
Tightening Sequence
Generally, when installing a part with several bolts, nuts,
or screws, start them all in their holes and tighten them to
a snug fit. Then tighten them according to the specified sequence
to prevent case warpage or deformation which can
lead to malfunction. Conversely when loosening the bolts,
n ...
Oxygen Sensor Installation (Equipped Models)
NOTICE
Never drop the oxygen sensor [A] especially on a
hard surface. Such a shock to the unit can damage
it. Do not touch the sensing part [B] to prevent oil
contact. Oil contamination from hands can reduce
sensor performance.
Tighten:
Torque - Oxygen Sensor: 25 N·m (2.5 kgf·m, 18 ...