Hello. I have a 07 Chevy 1500 4.8. 
I’m trying to narrow down why I keep getting 2 codes. Lean bank 1&2. It started will lean on bank 2. Now showing both. If I let the truck idle for a bit it’ll die. When I start the truck and immediately take off it’ll be fine. When I come to a stop for a minute then try to take off. It’ll stutter but eventually go. My power brake booster does have a “large vaccum leak” it also has a hose that goes to the back of my intake. Yes the booster has brake fluid in it from the master cylinder. Master cylinder is still full tho. I smoked tested the intake via booster hose. It did have a leak at a pcv connector. I fixed it. 
min still having the codes. I feel it can’t be the intake gaskets becuz no smoke. Can’t be the fuel pump becuz I’m still driving it. Past experience if it’s out It wouldn’t start. Would a brake booster cause this much problems or is it the fuel pump going out?