Power steering issues 2001 oldsmobile silhoutte

Hello, it's hard to say if the power steering system is causing the stall, or the stalling engine is causing the steering to get tight. Either way, I'd focus on the accessory drive area -- the part that the belt drives -- all the pulleys. If a pulley is hanging up -- whether it be a steering pump pulley or another component -- it can cause the engine to want to stall, and cause steering assist issues also. I'd have a look at the pulleys all the way around, by observing operation with the engine running, and then shutting it off and removing the belt to move all the pulleys manually and see if one is hanging up. Certainly, it could also be related to an engine performance problem, but I'd check those pulleys first.