rough idle
 

i have a rough idle keeps getting worse,when im stopped at a light its jumping up and down and if i have my subs turned up it about stalls out and if i put my rear defrost on.

Sounds lke you could possibly have a weak electrical system, like a weak alternator, or battery. That when there's a big draw on the system from your stereo, you're electrical system can't get enough power to the ignition system.

Just my thoughts.

I will agree with that. Makes perfect Sense.

I'll agree along with the guys.

Advance Auto and Autozone will tyipcially test both battery and alternator in the car for free. This would be a good start. Then probably checking the grounds etc.