micky wrote:
I have a 2005 Toyota Solara SLE, 133,000 miles, with P0171 and P0174
codes, lean mixture in both banks, and a check engine light that returns
soon after being cleared.

What are the O2 sensor(s) readings?
Can your scanner read or map the O2 voltages?
If not then use your dvm on the leads.
Check when HOT! 2k-3k rpm.