Es300 Misfires

[Stingry331]

Can anyone give me any input on there experience. I have a 1999 ES300 with codes P0302, P0304, P0306 and P0171, so all of bank 2 is misfiring and bank one has a lean code. Freeze frame data for P0171 code has bank 2 fuel trim at 50% all other values fairly normal.

All codes are set at the same time, if erased it takes a few weeks to come back on.

Any input would be great, thanks for any help I get.

Brett