P0171 to P0420 check engine 2000 toyota tacoma

[Mohammed ali]

About a week after I bought my tacoma 3.4 V6 the check engine light came on with a P0171 system lean in bank 1 code and I also noticed very poor mpg. The maf sensor was pretty dirty so I cleaned it with maf spray cleaner and reset the check light, mpg was instantly a lot better. I Thought that fixed it. Now a few days later check engine light came back on but with a P0420 catalyst system efficiency below threshold- bank 1 code. Also I believe mpg is low again, but not too sure. What should I do next? btw it has 150,000 miles. Thank you

Topic

[Its me]

Check the downstream O2 sensor is working properly with a scanner, check the inlet vs outlet temperature of the Catalytic converter. If the O2 sensor is working fine and the temps are not proper, then get a new catalytic converter…

-Karl

[Author]

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