no left turn !

I always end up with the good ones eh !LOL My daily driver 1997 Concorde LXI with the 3.5 SC in it suddenly decided to not turn left as I was turning into a parking spot . It has full power assist when turning right but seriously heavy armstrong steering when going left ,fluid is good and there is no pump rumble . Anybody know what is going on ? is it another stupid relay issue ? or is their a valve sticking in the power assist unit ? suggestions and ideas of repair cost greatly appreciated .
PS It seems to want to work when turning under acceleration and even did seem to work a couple of times on the way home when straightening back up after a right turn .