When I slow down my car dies. It starts back up right away. What is wrong ?

The check engine light hasn't been on and it is not on now

Okay , thanks for responding. My next question -when it stalls and then starts up again , does it start and idle as designed (normally)? When it stalls, is it more like the key was turned off or is it a gradual (albeit, relatively quick) smooth loss of power?

It stalls like the key was turned off and when it runs it kind of misses out at first but then runs smooth

Sounds like a faulty contact , but where that is , would need to be diagnosed with proper equipment , how consistently does this happen?

Just started after I had new battery put in yesterday

Aha! Always more to the story. That info changes the picture completely, I suspect that a 'memory saver' was not used during the battery exchange, thereby resetting the cars computer. That clears the 'learned' idle and other values. Try googling your year and model and engine , for proper 'idle learn procedure' or as in many cases I've seen , first start of the day , next time , with ALL lights and accessories OFF , start it and let it idle for 10 minutes , see if that helps.