2001 Sebring Convertible

I test drove this car and while on the highway the car felt as though it had a flat tire. After pulling over, there was no flat. Does anyone know what could cause this? I really like the car and the dealer says they will fix everything, but I am trying to be cautious.

Please Explain The Flat Tire Feeling

Was it dragging on one side?
Was it pulling to the right or left?
Would it track straight ahead if you let go of the steering?
Shaking?
Vibrating?
Shimmying?
Was there any evidence that the car had been in an accident and then repaired?
Had the spare tire ever been on the ground?
Dealer or private party seller?
You may need a second opinion other than the dealer.
Give a little more info, please.

Do you think they would go for a new set of tires?

Old School, I Think You Could Be On The Right Track!