The fuel filters were replaced at the same time as the fuel lines and o-rings. I took the intake crossover pipe off and cleaned it along with the flap. Both were dirty but not all that bad. The flap seemed to work fine using a hand vacuum pump. I did notice that the vacuum lines controlling the flap by the EGR valve and the vacuum line to the flap on the crossover pipe were cracked so I replaced both. I also swapped out the pressure sensor with another one of my cars that uses the same part (the problem didn't migrate to the second car). The car seems to be operating fine now ..... I'll test it on a longer freeway run over the weekend. Thanks for the suggestions.