jerking when changing from 1-2nd gear/auto trans

Ford Tauris have a bad reputation for transmission problems. Cheapest place to start (and to get piece of mind) is to remove the transmission oil pan change the filter and transmission oil and inspect to see if there is debris in the trans oil pan.

To supplement Patrick on this - that transmission was notorious for forward clutch pistons leaking pressure, causing hard shifting and engagement issues. The only repair to be done is to go through the transmission and overhaul it (or install one that has already been overhauled - a remaufactured unit). Now, you mention the problem has been going on for about 5 years...this is also fairly common with this problem! Folks like yourself can just leave it alone and keep driving, and it usually lasts quite a while. Can't say for how long, but since the only real alternative is a major repair - i'd probably keep driving it, being keenly aware of how it's running, and knowing when to stop driving if it appears to be worsening. Good luck.