Lean on both banks
 

97 with a 4.6L, getting lean codes on both banks.

I have pretty bad manifold leaks due to rusted studs on both sides, so I'm pretty sure that is causing my problem. On a cold day when they're leaking more, the exhaust is louder coming out of the manifolds than coming out of my Magnaflow muffler.


My question is this...

Money and time are tight, at least until the summer...so would you:

-bite the bullet, start drilling and tapping, and install some headers

OR

-JR Weld the living hell out of them and hope for the best

You may have bad header mountings but I honestly think you have an intake leak at some point from the mass air meter forward including the intake manifold hoses etc. It's unaccounted for air..
The lean codes is not the engine but what the PCM tables are presently shifted to (their lean end) trying to correct for excess air being detected by the OX sensors that try to correct the condition with too much fuel. The codes are the fnal result of the shift in tables
The codes mislead every one that don't understand how the system loop works.
Excess air at the manifolds would make the OX sensors try to richen the motor without sucess becasue no action can be taken on leaking headers.
Fix both and you will be good again

Check your PCV hose. Look close at the elbows for tears.