1998 Chevy Truck

My question is about steering. I loose power steering often. My pump has been replaced and I replaced the pressure line. My reservior has the sensor on it that goes to the fuel injection or something. Can the gut to that sensor be removed and my steering work better. Sometimes its working great until I have to turn into a parking spot and power steering just isnt there at all. I can start to turn the wheel put it in neutral rev the gas and the wheel will jump out of your hand and turn all the way in the same direction until it hits the bump stop. Then if you start to turn the wheel the other way while in drive and the rpms are low the wheel will be hard to turn until you rev the gas and the steering will turn the other direction all the way to the bump stop. Im aggravated