2002 Pontiac Grand Am Pontiac Grand Am 2002

I have a 2002 Pontiac Grand Am. Last week I noticed a vacuum leak and found it coming from the hose going to my Power Booster, from the Intake. I fixed the leak now the car idles at 400 after it warms up. Sometimes it will just die, at a light or other stop. If I remove the hose to the power booster, the idle problem goes away, but the brakes are hard to push… what is going on. Please help. I have a 2.2lt 4 cylinder engine with 225,000 miles on it. No smoking or overheating. Runs good other than above problem.