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 Holder Shaft Wear
The caliper body must slide smoothly on the caliper holder
shafts [A]. If the body does not slide smoothly, one pad will
wear more than the other, pad wear will increase, and constant
drag on the disc will raise brake and brake fluid temperature.
Check to see that the caliper holder shafts ar ...
Air Switching Valve Removal
NOTICE
Never drop the air switching valve especially on a
hard surface. Such a shock to the air switching
valve can damaged it.
Remove the air cleaner housing (see Air Cleaner Housing
Removal in the Fuel System (DFI) chapter).
Disconnect the connector [A].
Disconnect the hoses [B] from ...
Crankshaft Main Bearing
Insert/Journal Wear Inspection
Split the crankcase (see Crankcase Splitting).
Cut strips of plastigage to journal width.
Place a strip on each journal parallel to the crankshaft
installed in the correct position.
Tighten the crankcase bolts to the specified torque (see
Crankcase Assembly).
NOTE
Do not turn ...