My 2006 Sonata has 63K miles and today started jerking (Hunting) after about 10 miles. Here is what I know. It starts on a level run and disappears when on an incline, but as soon as the crest is reached, and on the downside, it starts hunting again. When it is jerking, around 55 to 60 mph, I switch the transmission lever to Autostick and it stops, back into drive again and it starts again. This is so repeatable there has to be a connection. EVERY time I switch to Autostick the jerking stops, end when I put it back into drive, it starts again. The jerking is severe enough that it is easily detectable. It appears that when the transmission is under load, like going uphill, the jerking stops.