Exhaust question/problem
 

Umm.. alright so because everyone is all like "ohoo neons in a mustang" I decided to bitch out and take them off, which is a pretty indepth job because of my friend's whack-job half-assed wiring. I had the stereo on and was pumpin it pretty loud so I turned on the engine to keep the car runing while I was taking out power... so I probablly had the engine idling for about... 30 minutes and I walked around back and saw a ****load of this watery-black-**** coming out of both pipes (more from the pipe that has the cat problem).

Can anyone tell me what that black-**** is and why its coming out of both pipes?

Soot, you are running rich or a cat is plugged.

I can see the cat problem but I'm not quite sure what that means, "running rich"? :confused:

Black residue means your car is running rich...

You are getting too much fuel that is just being burned off instead of being used.

What causes that, how can I fix it?

That happened yesterday when my brother turned on his car( it was wrecked) I thought it was from sitting but it could be a problem