Adjust the engine idle speed periodically on the engine at normal operating temperature.
To adjust the idle speed:

Engine oil and filter change
Throtile cable playEct sensor inspection
Refer to “dtc “c15” (p0115-h/l): ect sensor circuit malfunction” in section
1a .
Inspect the ect sensor in the following procedures:
remove the ect sensor. Refer to “ect sensor removal and installation” .
Connect the ect sensor (1) to the circuit tester and
place it in the o ...
Special tools and equipment
Recommended service material
Note
required service material is also described in the following.
“Exhaust system components”
Special tool
...
Inspecting the drive chain
When inspecting the chain, look
for the following:
loose pins
damaged rollers
dry or rusted links
kinked or binding links
excessive wear
improper chain adjustment
If you find anything wrong with the
drive chain condition or adjustment,
correct the pr ...