When the engine is running, the air intake valve is lifting up.
If the valve does not operate properly, check the air intake solenoid valve hoses for leak.
If there are no leaks, check the air intake solenoid valve.

Air Intake Solenoid Valve Unit TestSubthrottle Sensor Resistance Inspection
Turn the ignition switch to OFF.
Disconnect the subthrottle sensor connector.
Connect a digital meter [A] to the subthrottle sensor connector
[B].
Measure the subthrottle sensor resistance.
Subthrottle Sensor Resistance
Connections: BL lead [D] ←→ BR/BK lead [C]
Standard: ...
Fluid Level Inspection
With the brake fluid reservoirs held
horizontal, the brake fluid level must
be kept between the upper and lower
level lines.
A. Front Brake Fluid Reservoir
B. Upper Level Line
C. Lower Level Line
A. Rear Brake Fluid Reservoir
B. Upper Level Line
C. Lower Level Line
If th ...
Ignition Switch Replacement
Remove:
Air Cleaner Housing (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter)
Disconnect the lead connectors [A].
Remove:
Steering Stem Head (see Stem, Stem Bearing Removal
in the Steering chapter)
Using a small chisel or punch [A], turn out the Torx bolts.
...