Why Is P0171 So Controversial?

[artbuc]

RE 99 RX w/AWD @78k miles

I have read almost all threads in this forum re P0171. They mostly end in debates with no one ever telling what they did to resolve this code. Here are some of the sticking points:

1. One says 99% of time it is MAF and other says it is almost never MAF.

2. One says to clean MAF and many claim great results by doing so and others say it is useless to clean, you must buy new.

3. One says P0171 refers to bank 1 too lean so it can't be MAF while another says (correctly I think) P0171 refers to both

banks.

4. One says it must be A/F sensor while others say that is almost never the problem.

5. One says Toyota had a problem with ECU being incompatible with A/F sensor output and Toyota replaced under warranty.

I would like to hear from anyone who has had a P0171 code, without any other codes, who did something to permanently fix the problem.

Thank-you.