2005 Dodge Stratus 05 Stratus

Tires and Wheels problem
2005 Dodge Stratus 4 cyl Front Wheel Drive Automatic

Okay, I am having some issues with my car. Its a 2005 Dodge Stratus. It doesn't happen all the time, so that's why I am slightly confused by it. Periodically, while I am accelerating, the car hesitates to shift and ends up revving really high until it finally slams into gear. It normally happens between 2nd and 3rd gear or 3rd and 4th gear. I have also noticed that sometimes when I am stopped at an intersection or something, it will start to rev really high, like it is going to surge forward. But like I said, it doesn't happen all the time, but it has been happening enough to make me start worrying. I bought the car 4 years ago with 12k Miles on it as a certified car, so there is still a warranty, I just hate having to deal with the dealers if I don't have to.I have never had a problem with this car and it would really be a shame if it was something major, I really like it:( Any thoughts are appreciated!