I have a89 5.0 with some high performance stuff on it. Gt40 heads, cam, pro comp intake, 24lb.injectors , BBK headers, fuel pressure reg. And the car runs amazing once it's good and heated up. But when it's cold it got a studder or hard miss that feels as if the car shuts off completely for a split sec then hits hard when it comes back. It's real b bad when cold but once it warmed up it hardly ever does it. Any suggestions?