The large plastic-like gear that can be lifted out when the cover is removed: its the smaller circumference sprocket teeth on the 'bottom side' of that gear as well as the plastic teeth attached to the throttle plate that it drives. When those two gears that mesh together start wearing down there will be play between the two. The adaptive strategy employed by the ECM can compensate for this play that develops. However as the wear progresses/becomes excessive they start to bind and stick because the teeth start 'crashing' together at near right angles as they rotate into position which will at times act to lock up the entire mechanism. And for some reason colder ambient temperatures aggravates the condition, it may act fine at 60F but start sticking and binding at 20F (at least this was my experience, this wear should be predictably near identical between individual units when it occurs, so the temperature dependency should also be predictable/fairly consistent enough to be used as a diagnostic aid).oragex wrote: 23 Feb 2020, 10:48 You can also open the cover of these 2003-up throttle bodies. It's secured with 4 metal clips, just push them off, and you have access inside. As mentioned, the mechanism is really simple and looks robust, not sure what can go wrong with these but worth a close look for any damage to the gears, etc. I believe a used one should be a plug&play - to be confirmed.
The large circumference sprocket and the metal gear that drives it at the stepper motor that you see initially when you take the cover off isn't the problem. Because of the larger circumference of that gear there isn't near as much torque stress at that location and thus, no discernible wear that I could tell on either one that I've had apart which were affected by this wear issue.