2005 Chrysler PT Cruiser PT Cruiser 2005 convertible

Three weeks ago, I parked the car on an incline
driveway overnight. The temperature fell to about
20 degrees. In the morning, I put the car in Reverse and pressed the gas, the engine ran, but the car didn't move (as if it was still in park or neutral). The car jerked and then the car moved. I backed out of the driveway, put it in Drive and had the same result.

I was on vacation, so the next part of my trip was in warm weather and flat parking surfaces, and the car was fine.

Going home, I again parked cold and inclined and had the above result twice. I got home, and it has been cold at night, but the car is parked on a flat surface, and it is still hesitating, until it gets warmed up.

Once going, the car runs fine.

Can you suggest a possible problem?

Thank you.