My 96 Outback 2.5, hesitates when i have the a/c on , the idle and acceleration is sluggish. i have replace many components and also knock sensor , MAP sensor , clean the IAC, replace the fuel regulator valve and EGR valve. I don't know what to do next , I just bought park plugs wires and plugs . The funny thing is when i turn off the a/c the car runs fine. May be i'm missing something?