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"?

 

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