For the past month when i drive my 91 Integra LS on the interstate (any speed over 60mph) my steering is REALLY sensitive. Is there a speed sensitive valve on the PS pump that can be adjusted or a valve in the VSS where the power steering lines run to?

A little history on the car
4 months or about 1500 miles ago I bought new tires and an alignment. At that time all suspension parts checked out and were in good working order. My tire pressures are 34 in the front and 32 in the rear with 15" rims.