weird problem

[vish]

Okay so i changed my battery. I dropped the bracket that holds the battery in place down by the rear mounting bracket fished it out and put every back together started the car ran fine for about 3 minutes and it started running like shit. the car when it's running its around 500 rpms I popped open the hood and it sounds like there is a vacuum leak but I searched and searched and found nothing. So then I decided to take it out and see if it would run it out of its system. While I was driving the car will only boost to 4 pounds and has absolutely no power any input would be great. My car is a 95 Eagle talon tsi awd no mods bone stock.