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 TestSpring Preload Adjustment
To adjust the spring preload, turn the spring preload adjuster
[A].
The standard adjuster setting is the 6 turns in from the
fully counterclockwise position.
WARNINGIf both adjusters are not adjusted
equally, handling
may be impaired and a hazardous condition may
result. B ...
Fuel Tank Cap
To open the fuel tank cap, pull up the
key hole cover. Insert the ignition key
into the fuel tank cap and turn the key
to the right.
To close the cap, push it down into
place with the key inserted. The key
can be removed by turning it to the left
to the original position. Close the key
hol ...
General Lubrication
Lubricate the points shown below,
with either motor oil or regular grease,
in accordance with the Periodic Maintenance
Chart or whenever the vehicle
has been operated under wet or rainy
conditions.
Before lubricating each part, clean off
any rusty spots with rust remover and
wipe off any g ...