FUEL SYSTEM AND THROTTLE BODY 5-27 Step 3 • Turn in all the idle air screws to the complete close position. • Check for difference of vacuum between #1 and #2. • Equalize these two by gradually turning back the air screw on the higher vacuum side until the vacuum comes down to the lower. Similarly perform the same procedures between #3 and #4. • Check for the synchronization adjustment. If the adjustment is not yet correct, remove each idle air screw and clean them with a spray-type carburetor cleaner and blow dry with a com- pressed air. • Also, clean the idle air screw passageways. NOTE: * Slowly turn the idle air screw in clockwise and count the num- ber of turns until the screw is lightly seated. * Make a note of how many turns were made so the screw can be reset correctly after cleaning. Step 4 Repeat the procedures of Step 2 and Step 3. E USE OF VACUUM BALANCER GAUGE L Calibrating each vacuum gauge P • Lift and support the fuel tank. (5-3) • Start up the engine and run it in idling condition for warming up. M • Stop the warmed-up engine. A • Disconnect the IAP sensor coupler and remove the IAP sen- sor. (5-14) S • Disconnect the vacuum hose 1 from the #1 throttle body. • Connect one of the vacuum balancer gauge hose 2 to the vacuum nipple on the #1 throttle body.