So I figured I'd take advantage of the nice weather yesterday and get the stang out for a drive to fill the tank with some gas. Car was driving fine. One thing I notiiced was that the car doesn't get up to operating temp with the new t-stat, perhaps it's stuck open. I had the car idling to get it up to temp and make sure the electirc fan/DCC are working, everything was fine. This is where the problem begins. I shut the car down for a minute , go to restart, and it won't turn over. Pretty much imitated a car with a bad battery, but the battery is good. I had this problem some time back, and we thought it was fixed when the starter was replaced. Now I'm thinking that since it doesn't get up to operating temp due to the t-stat issue, the problem was never actually resolved (I haven't driven it much). So, where do we start troubleshooting a car that doesn't start when hot? Just as an fyi: about an hour later, when cooled down, it started with ease again.