Preliminary Throttle Valve Synchronization

With throttle body units properly installed, turn throttle stop screws of both units counterclockwise. Turn enough to break contact between screws and throttle lever tangs.
Adjust each screw to allow both throttle valves to close. Throttle rod end bearing will move freely on front unit throttle lever stud when both valves are closed.
Turn front unit throttle stop screw clockwise until it contacts lever tang. Turn 1/4 additional turn. Turn rear unit throttle stop screw clockwise until it contacts tang. Turn 1/2 additional turn. Perform final throttle valve synchronization on-vehicle with engine running. See "Fuel Injected Idle Speed (5.0L Engine)" in appropriate TUNE-UP article.
After performing idle speed adjustment, check throttle rod alignment. Push rear unit throttle lever to position both front and rear units in wide open throttle position. Push throttle valves in direction of arrows. Move throttle rod and bearing assembly toward front unit casting boss. See Figure .

Fig 1: Throttle Rod Adjustment This adjustment is performed after replacement of throttle body or manifold cover.
Turn front unit throttle stop screw clockwise until it contacts lever tang. Turn 1/4 additional turn. Turn rear unit throttle stop screw clockwise until it contacts tang. Turn 1/2 additional turn. Perform final throttle valve synchronization on-vehicle with engine running. See "Fuel Injected Idle Speed (5.0L Engine)" in appropriate TUNE-UP article.
Measure clearance at outside edge of throttle rod and bearing assembly on front unit. Clearance must not exceed .20" (5 mm) maximum. See Figure . If greater, replacement item must be exchanged and adjustment procedure repeated. If correct, install new throttle rod and bearing assembly retaining clip.
Move both throttle levers through total travel and fully close throttle valves. Push throttle levers in direction of arrows. Measure clearance at inside edge of throttle rod and bearing assembly on front unit. Clearance must be .04" (1.02 mm) minimum. See Figure .
If clearance is less than specified, remove throttle rod and bearing assembly retaining clip. Exchange replacement assembly and perform adjustment procedure again. After obtaining all adjustment specifications, install air cleaner and ensure no binding is present in accelerator and throttle linkages.