99 Stratus 'hesitating'

I have a 99 stratus that I've had for just over a year. Its got 97,000 miles on it. Its been running great up until last night. I was driving about 40 mph, and then all of a sudden, the rpm's went down to 1000, it jerked a little bit, and then went back to normal. Then this morning, on my way to work, the rpm's never lessened, but I was going between 55 and 60, and it would just hesitate. Kinda felt like it was sputtering. I have a good warranty on it, so Im taking it to the dealer to get it checked. But I cant get in until Thursday. I was hoping someone had an idea of what the problem would be.

Any help is appreciated!

THanks