Select your keyframes and open up the Wiggle Animation Assistant. Set the Frequency to one half of your comp's framerate and set magnitude to 0.000000001. Then click Apply. Then select all the keyframes and right-click on any keyframe and select Toggle Hold Keyframe.
broadcastGEMs - AEPro Volume 02 (Professional Adobe After Effects Project Files - Now Available). Adobe After Effects Training in South East Asia.
This would only apply the stuttering motion between the first and second keyframes as defined by the number in the key(x) parentheses.
When using the posterizeTime() function you can't use the 'value' parameter to return the posterized value, so you'll have to pickwhip the property to itself to generate the last line (i.e. "transform.position").