intake manifold gasket

[SYNY5TER]

so right now im having a P0171 system running too lean bank 1

cleaned the maf sensor
cleaned my bbk throttle body that has too much problem. idk if its that

im thinking it might be the gasket. idk how many miles this thing has but im assuming over 100k miles

how often should i be changing the gaskets?

also i have the charge motion delete plates

and also when im looking for a vacuum leak what should i be looking for in bank 1? i can only think of the PCV valve or watever

 

[Synyster06Gates]

Have you checked for an exhaust leak? That can cause the same code

 

[86GT351]

Exhaust Leak is a possibiltiy. Intake Gaskets can go bad. Especially if the manifold has been disrupted with the plates!

 

[Kalatrax]

O2 sensor as well but that will add in more than just a p0171 code typically. Those manifold gaskets are thick o rings. I've had my manifold off 10 times and haven't needed to replace them. Take some carb cleaner and spray around the manifold and intake tube while it's running. If there is a leak the idle will change.