2005 Other Toyota Models Suspect of faulty MAF Sensor

I have a 2005 Toyota Tundra, 6 cilynder 4.0 engine. In the last 2 days my engine has lost it's performance. I starts OK and runs but it misses and lost power under load at high speed. I took it to and Advance Auto Parts Store in PR, and was scanned. They just told me that 2 codes show up. P0171 and P 0174. System too lean bank 1 and2. They would not go any further, So I went to a Toyota DEALER and his service person told me the same and requested over 590.00 to replace the MAF SENSOR. I Refuse and cleaned the MAF sensor with a CRC special cleaner but it did not do any good. I check for vacum leaks and everything else seem to be OK, PLEASE Help. THANKS.