Q: Car stalling at stops and red lights

From the description, it appears that there are a few things going on with your Chevy Impala. A leak in the power steering system will cause the power steering pump to make noise and eventually fail. There are also a variety of things that can cause your Impala to stall when stopped. With so much going on with your Chevy, I recommend enlisting the assistance of a certified mechanic to come by and check out your Impala in person. They will have the experience and tools needed to identify why your Chevy is stalling and locate the source of the power steering leak. They will also be able to perform the repairs necessary to keep your Impala from stalling out and restore proper function to the power steering system.