Wierd Power Steering Malfunction... Pump???

Hi again. For those of you that don't already know, I've got an '84 Caprice, w/ the 305 & 4bbl Quadrajet. Lately, especially when its still cold, the power steering craps out on me. I'll be making a turn, and while turning the wheel the power steering will just stop working all together, and a few seconds later start working again. Also at times, it'll be very jerky (like it's having trouble) The fluid level is good, and I've even tried putting some Lucas fluid in. No help. Any ides? Is my pump shot, or is it something else? Thanks!

You May Have Internal Hose Damage. Sometimes The Inside Of High Pressure Hose May Go Bad And You Could Be Getting Chunks Of Hose Caught In Orifices In The Pump.