[bwood]

There is not a direct replacement intake that still uses the stock stuff. Have you checked your fuel pressure? It should be around 60 running and no lower than 58ish. Also, how many miles are on it? Once these engines start getting past the 150k mark, there can be enough wear on the dist gear that it can cause performance issues under light loads. Roller cams (like the stock one in the Vortec) are made of harder metals that will wear out dist gears. The stock dist gear is made special for the stock cam.