Stumped!

i just got done finding a new ground for it... and when i hook up the ground (i left the music running) it sounded good for a sec or two and it went back to bearly playing.. i am running 8 guage wire for the ground... i dont have a clue what is wrong with my system..

i have another question that might answer my problem... instead of running the rca cables i had to splice into the rear speaker wires and run wires up to the high input on the amp..the wires i ran from the rear speaker are the same size as the stock wires..do i need to put in bigger guage wires??

The high level input on the amp is not working with the deck.  It happens a lot, which is why I will always recommend using a high quality adjustable aftermarket line output converter instead of the amp's built-in converter.  And for your own safety and the health of your gear......like I said earlier in this thread and again was noted above, disconnect battery negative wire before removing ANY wiring.  Go through the steps.  Shortcuts lead to disasters.