Subs and loss of power

So here's the deal, have a 1998 jetta gl, and i was installing 3 10 inch subs with a box, in the trunk. I drilled a hole on the passanger side of the car, to put the rc cords through. I also pulled out the aftermarket stero to plug the rc cords into. After sending the wires through the engine and running them to the trunk, i relized that i need a box for the back of the stero so that the rc chords would work. I started up the car and the rpm's were very low (800) and i started driving and when i shifted into 2nd and the got the car going at about 25mph the car stalled, didn't die but the gas just cut out.

If anyine could help me out it would be greatly appreciated. Thanks.