2001 Kia Spectra

I have 2001 Kia Spectra and it has been really cold the past few days and my car will not go into drive or reverse until the car warms up and then it works fine. It worked like this for about 3-4 days. This morning was especially cold and it took like 30 mins to warm up to go. It was working fine and then it sipped out of gear and I pulled over to the side of the road and put it in park. I put it in drive and it jut revs up and doesn't go. Same thing for reverse, it goes in reverse but just revs up. What could this be?
January 14, 2013.

Sounds like the transmission is slipping -check the transmission fluid and condition if okay have it further checked

Jan 14, 2013.
It turned out to be the Safety Neutral Sensor. It sends a signal to the on board computer to engage the transmission and it wasn't registering the gears correctly so it would read like it was in neutral and that's why it would rev. Also tossed some lucus transmission additive in there. Total fix $25 for the sensor and $14 for the additive.

Jan 15, 2013.
Thanks for coming back with the fix-Good Luck and thank you for using 2carpros

Jan 15, 2013.