trac off light pontiac sunfire 2001

4 times in the last 2 months the "trac off" light comes on, 20-45 mph each time, transmission doesn't seem to shift or shifts hard after light comes on, 3 times car stalled.
4 spd automatic , turned ignition off and restart ..all seems ok.
any idea's

just a suggestion: did you see if the car had any codes in it?

just a suggestion: did you see if the car had any codes in it?

just now i did..err p0122...throttle position sensor tps- low input
thanks I thought when there where codes to read, the "check engine" would be on.