2019 Highlander Limited w/ 38k mi. Last week, "Check AWD System" warning showed up unexpectedly. Seemed to be running fine. Gas cap seemed ok. Codes were p0174 bank 2 system 2 lean and p0171 too lean. Checked air filter, ok and took off and inspected mass air flow sensor and seemed fine. Noticed after starting it idle low and i had to "pepper" the gas to keep from stalling. Put in a bottle of Chevron Tekron and filled up tank and cleared codes by removing + terminal of battery. Wife drives 5 hrs (seemed to do fine) and after gas fill up, trouble starting and codes return. Local independent mechanic in area said multiple codes (p1603-1605, c1241, b124b, b150a, c1aa5), thought it was likely an electrical issues given various codes. Replaced battery, as it was reading "low" (was 3yr old) and "give it a try". Seems to be idling rough and problems seem to arise when stopping and filling up the gas tank. Any ideas/thoughts? Much appreciated all for your input.
