Toyota 4Runner Forum - Largest 4Runner Forum

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- 4th Gen T4Rs (https://www.toyota-4runner.org/4th-gen-t4rs/)

- - P0174 help (https://www.toyota-4runner.org/4th-gen-t4rs/294587-p0174-help.html)

I have 2007 v8, hydro locked the motor last year, put in a used replacement and have about 10k on the new motor! Every 900 miles or so it is throwing a p0174 or Lean Bank 2 code! Replaced both down stream 02 sensors last week and now the code comes on within a few minutes of being cleared! MAF has been cleaned, the intake gasket was replaced when the motor was installed, and can’t find any loose vacuum lines!

So I’m down to a fuel issue or the air fuel sensors! I have the intake, fuel rail and injectors off my old motor and thinking about swapping the injectors out, before spending the $300 on air/fuel sensors!

Any other ideas?

Quote:

Originally Posted by 94toy22re (Post 3599936)

Check for exhaust leaks. I had this same code in the past, it was because one of the flange gasket that mates the exhaust manifold to the y pipe was rotted away, allowing tons of air to escape. I discovered it by starting the car and just rolling underneath and placing my hands around everywhere there is an exhaust gasket, feeling for air that was escaping. Running lean = O2 sensors thought there was not enough oxygen because it was all escaping out of the exhaust leak. $5 gasket later, no more CEL.