I bought a used 02 focus with 15000 miles and an automatic transmission in spring of 03. It has always has this lugging shaking problem when I'm accelerating. As I'm accelerating it revs too high and finally makes a noise and a luggin/shaking motion that lunges the car forward as it goes to the next higher gear. The problem only gets worst when the AC is on. I'm having this same problem when I'm decelerating. I've taken it into the dealership twice for this problem once they allegedly recalibrated the software that decides when to shift. And the second time they replaiced the coil pack on the #2 cylinder. Neither fixed the problem. Last week this same problem occurred except this time a light came on, it wasn't the check engine light, I looked at the manual and it's the light that's for automatic cars and zetech engines, it also said to have car serviced. I've driven the car since then and the light hasn't come on again but the problem still exist. Please help.