TC lumagny

Hello
I turned on my CTS 2003 at morning I found the light TC turned on. I tried to move the selector it was blocked on P. I just turned the ignition and selected Neutral and turned on the car it worked. I connected the scaner, it gave the stop lamps are broken. I changed the stop lamps and cleared the memory, the car worked normally for two hours and turned off alone. I turned it on, the accelerator pedal didn't work. I turned off and turned on the car it worked badly for 10 minutes and stopped completly. I waited 2 hours and turned on the car it works normally. Could any-one explain me what happen?