2003 cavalier stalls ???

every once in a while my 03 cav will stall when braking for a stop sign. But, recently it has stalled while in park warming up, also it stalled 4 times while driving in one day I thought maybe it was bad gas because it ran better after i got more gas in it however the hose running to the power steering pump has a small leak and is hissing can the power steering leak cause it to stall. The Power steering pump does not run off of a belt so i thought maybe it ran off of engine vasuum and the leak is causing it to stall.

well I`d fix the vac leak and also get the fuel pressure checked , change the fuel filter if it has not been done in a while . sounds like it could be the fuel pump or regulator starting to go south. read this http://www.automotiveforums.com/vbulletin/showthread.php?t=671060

I've never heard of a power steering system running off of vaccuum but power steering pumps will a lot of times sound just like a vaccuum leak. Is your check engine light coming on?