Please Help My Lean Codes

[myblueheaven]

Not sure why this didn't post, but here goes again.

I keep getting lean codes P0141, P0171, P1150. I think I have had several O2 sensors replaced. I have check for vacuum leak with smoker and checked vacuum pressure, replaced mass air flow sensor, changed the PCV valve, changed the plugs and coils, checked fuel pressure, ran a can of Seafoam through the gas.

None of this has helped. I still get lean codes and I am getting about 13 mpg.

This is a 2000 Lexus RX300 with 135k miles. This has been a problem for a couple of years now but my mechanic can't figure this out.

It has not been a higher priority because I only drive the car about 10-15 miles a day.

I don't want to keep throwing money at it, but I do want it to run properly.

Any help would be much appreciated!