2000 Lexus ES300 with 155000 miles - CHECK ENGINE and TRAC OFF lights ON - CODES P1130 and P0330. Vehicle would NOT shift into overdrive (3rd shift of transmission during acceleration). Sometimes systems would reset after shutting OFF engine or deceleration in traffic, but overall the problem persisted. Purchased an Autel MaxiScan MS310 OBDII/EOBD Code Reader on Amazon (Prime) for 25.50. Codes read P1130 which translates to AIR/FUEL SENSOR. Not sure which Bank or Circuit. Also KNOCK SENSOR BANK 2, CIRCUIT BANK 2 (P330). I attempted to R&R the AIR/FUEL SENSOR myself located at the rear of the engine forward of the firewall. All forums described this as difficult to reach. I used the TEKTON 4929 3/8-Inch Drive by 7/8-Inch Oxygen Sensor Socket purchased on Amazon (Prime) for 9.51. The Sensor was difficult to reach and I couldn't get the leverage needed. Decided to seek professional help at a local independent shop because dealers are a ripoff. Case in point: One ES300 owner took his vehicle to the dealer and spent 1200.00 replacing the O2 Sensor and the problem was not fixed. My shop too had problems removing the sensor (stuck). Had to remove the exhaust manifold to get the needed leverage. Turns out the threads were stripped. Vehicle taken to the exhaust shop for this procedure and re tapping. Vehicle transfer was done by my independent shop. I was entirely hands off. The Air/Fuel Sensor was R&R'd. However, the problem was not fixed so shop proceeded to R&R the KNOCK SENSOR BANK 2 (under the forward intake manifold). Saw a YouTube video of a guy doing this in his garage - made it look easy, but the intake manifold was already off. I had a Valve Gasket leak so the shop R&R'd the Valve Cover Gasket at the same time (virtually cost neutral). Vehicle was in the shop one week and test drove by the mechanic after work complete. ALL good. However, when I left the shop I drove home and was disappointed to see the CHECK ENGINE and TRAC OFF lights illuminate on the second segment of my freeway drive. The ABS light also illuminated. I drove several more segments exiting the freeway, stopping, and starting again. On one occasion the vehicle did not shift into overdrive (3rd shift of transmission during acceleration). Subsequent evaluation showed only Code KNOCK SENSOR BANK 2, CIRCUIT BANK 2 (P330). The CHECK ENGINE and TRAC OFF light presented several more times during the first 80 miles of driving after maintenance, during which overdrive failed once (as described). Vehicle now has 250 miles since maintenance with NO SUBSEQUENT ISSUES or abnormal light indications. Perhaps the engine had to adjust to the new sensors. ALL good for now while cautiously keeping my fingers crossed. Happy with the final bill considering the work that was done. 1107.00