First I noticed the engine temp gauge was jumping all over. I checked out the engine myself each time it peaked and said it was over heating and everything was fine. I was resigned to dealing with the light, until we had a cold snap and I couldn't start my car. It would just crank and crank and would take up to a few minutes to start. I took it to the shop and after a day and a half of troubleshooting (I lucked out and they only charged me for the the part and the labor to actually change the part, not the troubleshooting) they found that the temp sensor was physically broken and there was a dead shorting through the fluid. He said on this model the computer uses the info from that sensor to determine how much fuel to give the engine to cold start. the computer thought the engine was warm (actually over heating) so it wasn't getting enough fuel to start during the cold weather.