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Q: Too lean in bank 1 and bank 2

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My truck has recently been serviced. I have had the O2 sensors replaced. Check engine light came on and said P0171 and P0174 too lean. Is that issue the amount of air that is getting into the system and not enough fuel?

My car has 270000 miles.
My car has an automatic transmission.

A: Hi and thanks for contacting YourMechanic. ...

Hi and thanks for contacting YourMechanic. When the engine becomes too lean, then combustion chamber becomes very hot causing the head gasket to burn, valves begin to burn, and the rings being to seize up. Check the camshaft sensor and MAF (mass air flow) sensor to ensure that they are working correctly.

The reason the sensors are pulling up the codes is they are working and saying that the system has loss of fuel (hydrocarbons). Also, check the fuel injectors to ensure that they are operating properly. I recommend putting in an injection cleaner to clean out the injectors for a better atomization spray. If you need further assistance diagnosing your Check Engine Light, then seek out a professional, such as one from YourMechanic, to help you with your vehicle.

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