[green Deville]

I need to know if anybody has expierienced a simular problem such as mine. I need to know where to direct most of my attention at. The answer is probably simple but finding out what it is is the part that I am having problems with. My caddy cut off one day needing a tow home and now it works fine in the driveway. I dont want to take it out because i have a feeling that it might quit again since it already did once. There's definitely a problem because it needed a tow. Even though it's not cutting off now. Any ideas? Anybody? This morning it ran for 45 mins without cutting off in my driveway. I know it might not be the same as driving around town but I didn't need a tow. lol. please help me somebody.