[edgeleycanuck]

I have just recently had my truck wired and fired by a local performance shop. I have only started it maybe 10 times and driven a couple of miles. It is a used 4.8 out of a 2000 pickup. On initial startup it has been running very rich especially when cold, it now is not starting with out some throttle, I have not checked for codes yet, the wiring harness is new as are the oxygen sensors. The mechanic asked me if the intake gaskets have been changed, I bought the engine in a wrecked donor vehicle so I don't know. Long story short he said the truck intake manifolds are known to fail( not sure of which model years), he said the engine draws more air and wants to add fuel.... Anyway I have no idea if my blathering is helpful but just wondering if the possibility of a vacuum leak you mention could be an intake gasket failure?