The car seems to speed up suddenly sometimes and then seem to not want to speed up or maintain speed especially on interstate traffic. (I dont go on interstates often). On normal 50-60 speed it does fairly well. after reading the other complaints on ford taurus transmission problems worried it may be an expensive repair if I can find out what needs to be fixed. Also noticed the rpm speed up and slow down repeatedly when I am maintaining the same speed. could this be dangerous?

Update from Jun 25, 2013: transmission will only go in reverse or forward like it is in 1st gear

while moving at a steady rate of speed, it begins to jerk as if trying to find a grabbing point in the gears. it seems to be that it is slipping in second or third gear. at times I feel as if it is caused by a transmission mount, like in the earlier Taurus, or as if teeth have been chewed from the actual internal gears. if all that made sense. I've been lead to believe that 'Lucas oil' transmission fix/slip stop fluid would fix it, my tire dealer told me this!? is he accurate or is he just trying to sell me stuff? I do enjoy my car, I bought on my own 2 years ago. is this something I can fix and not regret it, or should I enter it into a roll over contest and get another used car?