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 TestRear Caliper Removal
Remove:
Bolt [A]
Rear Wheel Rotation Sensor [B]
Loosen the banjo bolt [C] at the brake hose lower end,
and tighten it loosely.
Loosen the caliper holder pin [D].
Remove the rear wheel (see Rear Wheel Removal in the
Wheels/Tires chapter).
Unscrew the banjo bolt and remove t ...
For Primary Fuel Injectors
Remove the air cleaner housing (see Air Cleaner Housing
Removal).
Disconnect the primary fuel injector connector [A].
Connect a digital meter to the terminals in each primary
fuel injector [A].
Measure the primary fuel injector resistance.
Primary Fuel Injector Resistance ...
Radiator Cap Inspection
Remove:
Radiator Cap (see Coolant Change in the Periodic Maintenance
chapter)
Check the condition of the bottom [A] and top [B] valve
seals and valve spring [C].
If any one of them shows visible damage, replace the cap
with a new one.
Install the cap [A] on a cooling system pr ...