Sounds like you have air in the lines. Try bleeding them and see if that helps. That was my problem.

Black Sapphire '96 RS w/ Blitz Kit
AEM CAI,AFX UDP,Apexi N1 Exhaust,NGK BKR-5e11 Plugs,Magnecore Wires,Primax 496 17's w/ Falken Azenis Tires,Blue Interior Lights,Greddy Shifter Knob-Boot-Pedals, TYC Black Taillights