A friend of mine has a 97 Tahoe with a Vortec 350... Not long ago someone replaced the intake gasket and it hasn't runned right since. From idle until right before aroudn half to 3/4 throttle, it runs fine. But after that it bogs down and has no power. When this happens the sucking noise from the air cleaner gets very loud. It blows no smoke when this happens so were thinking its not being overloaded with fuel. I am wondering if it could possibly be a timing issue or a TPS..... Anyone?