Jerk when Stopping

My windstar has for a while been making moderate/slight jerks when stopping. It tends to happen typically just before coming to a complete stop, although sometimes it happens during low-speed turns when coasting (also sometimes have the issue where it shifts downshifts harshly after a "sweeping turn," as mentioned in one of the windstar TSBs). The RPMS don't appear to visibly drop when it occurs (although the tach in the 'stars seems a little slow sometimes). The only trouble code present is P0133 for the Bank 1 downstream O2 sensor slow response.

Also, it tends to worsen when the car is warm. The jerking is less severe when the engine is cool, and tends to worsen after the car warms up. Also it sometimes almost feels like the jerk occurs in two stages. I do not believe it is the TCC solenoid failing to disengage, due to the fact that it even happens if I get up to 15mph for a hundred feet, and then stop.

Probably unrelated, but the car also tends to run rough for 10-15 seconds after starting the first time if left sitting for a few days.

Anybody experience this? Any ideas on what it might be?