Concorde 3.2L V6

• Automatic transmission
• 134,000 miles

I was just wondering if any one could help me a little. When i take off my car wants change out of second gear. I can put it in neutral and turn the key back and kill it and restart it and it will shift out and do fine until i slow down and then it will jump and lug down in gears again. Then I have to restart and do it again to get it to do right. Starting to slip some it's tollerable when you first crank and drive it, but later on down the road it'll start slipping where you can give it gas and the rpms will rev up and the car won't pull that hard at all wondering if someone might know the problem and please try to save me some money thank you