Vacuum Throttle Modulator: Servicing

The decel valve calibration is preset at time of manufacture and normally does not require adjustment. If adjustment is required, go to next step.
With engine not running and curb idle speed previously set, position throttle lever against curb idle adjusting screw. Measure clearance between the throttle modulating diaphragm plunger and throttle lever. It should be 1/16". Adjust by loosening the jamnut and turning the diaphragm assembly.

Fig 1: Jeep Throttle Modulating System (Decel Valve)

Courtesy of CHRYSLER GROUP, LLC