1999 pontiac firebird bank 1 and 2 lean help?

[FattMatt]

I have bank 1 and 2 lean codes p0171 p0174. i have cleaned the maf twice and changed the fuel filter. i checked fuel pressure and it was good and i fixed one small vacuum leak cleaned pcv and checked for other leaks. took it to get looked at and they said i need a throttle body gasket and new purge valve so i got that and didnt fix the problem then they said it was my intake gaskets so i replaced both upper and lower intake gaskets and still didnt fix the problem. i took off the egr and cleaned it out real quick with brake cleaner and started the car and the light went off. drove it 3 miles and the light came back on still lean on both banks. i tried to reclean the egr to see if it would turn the light off again if i did it and it did nothing. Ive read about not doing the o2 sensors because they are unlikely to both go out at the same time but idk what to do anymore and i dont want to take it in and get charged 80 an hour for just labor or something. does anyone have any good advice or had this problem and fixed it? help please and thanks. also idk if it matters but the emissions place said my gascap wasnt making a good seal idk if this could be considered a vacuum leak of some kind too????