Regarding my 04 Camry 4 cyl., I have done some reading and have come to understand that there could be a few reasons I am getting the P0171, but I have to say that the car runs great and no excessive fuel consumption either. So what would be the most economical first approach to resolve the issue? I have seen posts that recommend engine, or fuel injector cleaners to stuff to clear out the crap in the catalyst. Is there any good reason that I should consider doing any of this, or I should just go after changing sensors?

 

If I remember right the p0171 is system too lean code, right? If it is, the best place to start is by cleaning out you Mass Air Flow sensor. It should be located between the air filter and the intake plennum. Good luck.