Connect a commercially available vacuum gauge [A] to
these right fittings of the throttle body as shown.
Connect a highly accurate tachometer to one of the stick
coil primary leads.
Vacuum Switch Valve Hose (Thick) and its Air Cleaner
Vacuum Switch Valve Vacuum Hose Ends [C]
Air Cleaner Housing [A] (see Air Cleaner Housing Re-
moval in the Fuel System (DFI) chapter)
Vacuum Gauge [C]
Extension Tube [D]
Special Tool - Extension Tube: 57001-1578
Start the engine and warm it up thoroughly.
Check the idle speed.
Open and close the throttle.
If the idle speed is out of the specified range, adjust it.
Do not measure the idle speed by the tachometer of
the meter unit.
While idling the engine, inspect the engine vacuum, using
the vacuum gauge [B].
Standard: 27.3 ±1.333 kPa (205 ±10 mmHg) at Idle
Speed 1 300 ±50 r/min (rpm)
If any vacuum is not within the specifications, first syn-
chronize the balance of the left (#1, #2) and right (#3, #4)
#1: 165 mmHg
#2: 190 mmHg
#3: 170 mmHg
#4: 200 mmHg
With the engine at the correct idle speed, equalize the
lower vacuum of #3 and #4 (example 170 mmHg) to the
lower vacuum of #1 and #2 (example 165 mmHg) by turn-
ing the center adjusting screw [A].
Special Tool - Pilot Screw Adjuster, C: 57001-1292
PERIODIC MAINTENANCE 2-19