I also have the P0171 code on a 2000 Lexus RX300 with 71K. Have been taking it to a local Toyota aftermarket repair center. They cannot determine what it exactly is so have not replaced it. They have reset it a couple of times and have about 2500 miles additional on the car since the first Check Engine light. Just got it checked again since the light came on after being off for a couple of months. The dilemma here is that now we are on a drive to Alaska and can't have it fixed until we get there. The shop said not to worry it will be fine but in the first half of the trip we have been getting BETTER gas mileage (I know I shouldn't complain) but my concern is the overall health of the engine. Trying to get an opinion on if we will hurt the engine overall. We have about 1500 more miles to go.
