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Q: Bank 1 too lean

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Check engine light is on got it tested and it said Bank 1 too lean do I need to change my O2 sensor or egr

My car has 174116 miles.
My car has an automatic transmission.

A: While a bad O2 sensor can be the cause of a...

While a bad O2 sensor can be the cause of a 'lean" fault code, it can be set for a number of reasons. A vacuum leak anywhere in the intake system can cause a lean fault as can other sensors like the mass air flow sensor. Also, any bank 1 cylinder that may be misfiring due to a faulty spark plug, ignition coil, or improperly firing fuel injector can set that fault. A certified technician can diagnose the why the check engine light is on to isolate the exact cause of the lean fault code being set.

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