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 TestMaster Cylinder Inspection (Visual Inspection)
Remove the master cylinders (see Front/Rear Master
Cylinder Removal).
Disassemble the front and rear master cylinders (see
Master Cylinder Rubber Parts Replacement in the Periodic
Maintenance chapter).
Check that there are no scratches, rust or pitting on the
inner wall [A] of each ma ...
Oxygen Sensor - not activated (Service Code 33, Equipped Models)
Oxygen Sensor Removal/Installation
Refer to the Oxygen Sensor Removal/Installation
(Equipped Models) in the Electrical System chapter.
Oxygen Sensor Inspection
Remove:
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Oxygen Sensor Lead Connector [A]
Connect t ...
Alternator Rotor Removal
Remove the alternator cover (see Alternator Cover Removal).
Clean off the oil from the outer circumference of the rotor.
Hold the alternator rotor steady with the rotor holder [A]
and suitable washer or plate [B].
Special Tools - Grip [C]: 57001-1591
Rotor Holder: 57001-1666
Flywheel P ...