I am having kind of the same problem. just at idle is fine. When you start to step on it, it stubbles and starts to get better as the rpm increases. But still not right. I'm going to try a set of plugs. If that dosn't do it, good bye funel Web. The only differents between mine and yours is my came is 575 lift, and I have an AEM 750 holley double pumper. I should have tried the Funnel Web intake with my old motor.