2004 freestar jerking

i have a winstar that jerks when you put it in reverse and backup or you put it in drive and move forward,clears up when you start to give it more gas. think it has aliittle jerk when driving but not very pronounced yet. Also seem to be getting poorer gas milaege then I was before it started doing the jerking. could it be a the coil starting to break down?

2004 Freestar has been plagued with transmission problems. You can read over 100 posts at this link.

http://townhall-talk.edmunds.com/direct/view/.f0fb94a/60

Maybe torque converter.