Evan Dodd

Having trouble fighting a vaccum leak or so I believe with my 2000 Silverado 1500. Has the 5.3 in it. I have po171 and po174 lean codes and that’s it. Leads me to believe that it is caused by a vaccum leak. Already did intake manifold and have used smoke which led me to a leaking gasket on the egr, but the codes still come up once the truck completes its cycle. I just want to know if there are any other common leak points I have overlooked or what else could be causing these codes.