Hey Scotty,
My ‘07 Corolla LE A/T is throwing code P0171. So far, I have checked for vacuum leaks, including the intake manifold, replaced the air filter, cleaned the throttle body, cleaned the MAF sensor, and replaced the upstream 02 sensor. The car is running much better, and live data on my scanner shows it running much less lean. However, the code continues to come back. Live data shows the upstream 02 sensor reading at 3.3 volts no matter how long the car is driven. I have not yet checked the fuel system. Any thoughts on what we might be dealing with? Thank you kindly for all you do.
Ethan
Clarification: Mileage and which engine?
My apologies, mileage is 104k and engine is 1zzfe. I have changed the PCV valve and run fuel system cleaner - chevron techron. Fuel system test is the next item on the agenda as well as coil packs. Any ideas why live data might show proper levels and 02 sensor still reads high voltage?
I would do the following; get a mechanical fuel pressure test, get a new PCV valve, check all coil packs for proper function and run some fuel injector cleaner through the system.
