Does not Stay running at traffic lights

What is your question?

This is an intermitted problem. Usually it will start right back up but today it would not turn over. a jump helped but it turned over when the positive cable was disconnected.???? Is it possible to have a bad ground in the ignition circuit. I did test the battery and its fine. At first I thought it was a vacuum hose and torque sensor in the tranny not engaging when I slowed down. But now its doing it in park with a low idle. I also hear a funny click when I turn the key sometimes. If I don't hear the click when I start it the truck runs fine, when I do hear the click it runs like crap. this truck also has a plow mount on it. Any advice would be great.