2005 Mercury Marquis Engine spark

i wired up subwoofers in my 2005 mercury grand marquis and now i have a serious problem. when i turn the key to accessory the car jumps, almost like its trying to start, then when i do start it, it runs then makes the screeching noise like the one you get when you start a car thats already started. I ran the speaker wire thru the fire wall under the pass side. I used the pre-existing hole there that was for other wires.i look at those wires and they look like they lead up to the dash somewhere, im not sure tho. please help, this is making me sick just thinking about it.
Also i unhooked everything for the subs and it still does it
and the car still throws a spark