jerky taurus

I have a 93 ford taurs that jerks violently sometimes at about 25 to 35 mph and will kick down for no reason at cruising speeds. a guy at autozone told me i need a tourque converter lock silenoid but i dont know it has a 3.8l v6 with the 3 speed auto overdrive. other than that problem which I admit is pretty major the car is great and always was up to a year ago when it started doing that jerky thing. any help woul be greatly appreciated. it was a great winter car but now it wants to spin the front tires when it is acting up. thanx in advance,
jarrod

Iv seen several taurus's with the same engine have huge problems with the transmission. It wouldnt surprise me if it was the torque converter had some problems with it. The high rpm might be some fluid problems