1998 Taurus power steering quits working

I recently bought a 1998 Taurus GL with 73,000 miles and very clean and nice. The power steering will work for a little while right after starting and quits and then gets stiff like no power at all. In the morning after starting it works while backing out of driveway and before I drive fifty yards it quits. I have had a new Rack installed with no results. I then changed the pump and filter with the same results. I am at a loss at this point. There are also no crimps in either of the incoming or out going lines. HELP?

This may sound stupid, but look at the Transmission Range sensor on top of the transaxle. It has a lot of circuits running through it and one os for the power steering pressure switch.

Make sure the system is bled completly. While the car is running, check the fluid level and then turn the car off and check the fluid level. See if they are the same both times.

We checked this sensor and seems to be working fine. Also checked the two solenoids on the Rack and they both were working. Did find excessive trash (paper/cardboard???????) in the line just before the filter. Blew it out and thought it was fixed (*_*). Had to put on another new pump. The other had burned up with no fluid going through(my poor hearing evidently). Now I am back to squre one with no idea who or where to take it now. Help Again

Some of the taurus's have a variable assist control. It consists of a control solenoid and the GEM module (like a body control computer). When there is low or no voltage at the rack mounted solenoid, there is little p/s assist. You can check the solenoid with a volt meter. The one I had was VERY intermitant. We replaced the gem module first than the solenoid.

Good Luck
Rob

Thanks Robert 1010, I will check this suggestion first thing in the morning. This may be the key to a solving this riddle (my headache) and certainly sounds very feaseable to me. Certainly appreciate the advice!

Thanks folks, checked sensors and were OK. Friend thought the new rack was bad. Changed the rack AGAIN and everything is good. Power steering is great. Appreciate all the help. Thanks again!!!