System Too Lean Bank 1 and 2

[BENC911]

I took it to the shop and the car shows those system too lean in bank 1 and bank 2, do i have to replace anything? 

 

The mechanic told me we should replace the coils in #4 and #5 because they are misfiring due to something. 

 

Any ideas before i go buying new coils?

[Loren]

Exact model and year of your car please?

[BENC911]

Sorry I always forget 2011 911 carrera S convertible


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[BENC911]

any ideas? should i buy the coils ?

[Loren]

Could you please give us the exact fault codes?

[BENC911]

That is what i get.....i will re run the codes, but i think that is what i got before

[Ahsai]

I think what Loren meant is the actual error code such as P1128, P0300, etc.

[BENC911]

Sorry these are they:

 

P0175

P0171

 

 

[Loren]

P0175 Oxygen sensing adaptation Bank 2: System too rich

 

Possible fault causes:
- High fuel content in engine oil
- Exhaust system leaks (Engine A Oxygen sensor in front of catalytic converter )
- Injection valve Faulty (Mechanical fault )
- Timing incorrectly set
- Fault in area Fuel high pressure,  Intake manifold pressure sensor, Throttle adjusting unit, Ambient pressure sensor, Intake air temperature sensor, Speed sensor, Valve lift
control, Camshaft adjustment

 

P0171 Oxygen sensing adaptation Bank 1: System too lean

 

Possible fault causes:

- Exhaust system leaks (Engine A Oxygen sensor in front of catalytic converter )
- Exhaust system Narrowed / Blocked
- Injection valve Faulty (Mechanical fault )
- Timing incorrectly set
- Fault in area Fuel high pressure, Intake manifold pressure sensor, Throttle adjusting unit, Ambient pressure sensor, Intake air temperature sensor, Speed sensor, Valve lift
control, Camshaft adjustment

 

I do not see anything here about misfires or coil issues.

I think you will need more investigation here. I have seen a car with too lean in in bank and too rich in the other bank. Almost makes me think a fuel line might be blocked on one side causing over-pressure on the other side.

Perhaps others can chime in...

[BENC911]

They checked the fuel line ( did a smoke test ? ) and nothing............. Ideas?

[JFP in PA]

This is going to require several specific tests, you need to find out what the intake vacuum level is at idle and at an steady engine speed (around 2,000 RPM steady, not revving the engine) looking for a possible exhaust blockage,  You need both low and high pressure fuel pressure readings, you need to check the cam and valve lift actuations for correct movements, etc.

 

This type of problem requires sequential elimination of each of the possible fault causes listed in Loren's post.

[BENC911]

Thanks, i will communicate this to the mechanic!