Had the same problem on mine and found that it was in the idle circuit just off idle as I moved off from a dead stop . Changed the idle feed restrictor jets ( everyone does have removable hi speed , idle air bleeds and IFR jets don`t they ??
) from .035" to .037" on the secondary side and eliminated 95% of the problem . The .035" are stock on the Holley I have . I`ll replace the primary IFR jets this weekend and that should eliminate the problem completely . I also have the ability to change the transfer slot restrictors , so I have another avenue to explore .... or screw up on .