On my 99 V6 automatic, at lower speeds and around-town driving, it won't downshift unless I floor it, and it seems to lack power. But when I'm on the highway, in 3rd and 4th gears, it will take off like a son of a gun and has a lot of get-up-and-go power. I got back to my neighborhood, and I dropped the shifter all the way down to "1" and I gave it the heavy foot treatment, and it just jerked and chugged, and acted like it wanted to die. So I stopped, put it into drive, and it was fine. Any ideas?