car stalled then when restarted it blew muffler apart any ideas?

Welcome to AF!!

Sounds like the car was flooded and when it stalled the fuel got inside the exhaust and then exploded when you restarted it. You could have a sticking fuel injector that is causing the excessive fuel or it may be just an odd happening. Check your plugs to see if they are fouled due to excessive fuel in the cylinders. This will probably be the only way to tell what is actually going on inside the cylinders.