weird steering problem

i have a 99 silverado and i have a prob. when i back out of my driveway and i put it in drive and turn to go up the street, it feel like i lose power steering completely. sometimes i also hear a groaning noise while im turning at about 5-10 mph i have checked fluid, flushed it, and bled it with no improvement.

There is a steering censor that might need to be replaced but only a dealership could tell you for sure. I had mine replaced in my 98 and it was about $75