I talked to the place the installed it, and I had then put in the Cadence Heavy Power Starter Kit and all that ****, and they said that they may be picking up the signal from the alternator and feeding it into my subs. Because when I don't have the engine on it is fine. No buzzing.
You're getting feedback through your power wire then...if you don't have shielded wire it may be worth the investment. Also...if your rca and power wires are run on the same side of your car you will be getting some interference as well. Are you experiencing any popping sound when you cut off the stereo and the amp cuts off? If so I would definitely invest in shielded wires and get something to insure the interference isn't carried to the amp, not good at all for the amp.
I went to the place and he told me that my factory amo is going to hell. The sound in the front is fine, but it is the back speakers that keep crackling, so I think I will just unhook them for now; then get some new ones when money permits.