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P1287, P0393, P0391, P1073 faults System too lean at idle bank 1/2

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Not able to understand what could have caused these fault in 08 Cayenne Base. Please guide me on how to further investigate this

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Overly lean conditions come from a couple of issues: insufficient fuel (low pressure or volume flow, plugged injectors), or intake vacuum leaks allowing too much air into the combustion process.  As it seems to be on both banks, I would be looking at testing the fuel delivery system, or smoke testing the intake system looking for leaks.  With the high idle fault, it is most likely a vacuum leak.

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There was a vacuum leak. Break booster hose was split, have replaced it. System too lean codes have cleared but below two codes(P1073 and P1057) have persisted




Please advise how to solve this.

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  • 3 weeks later...

Tried clearing the codes 4 times, but P1057 and P1073 keep coming back after driving some miles. Any insight on how to check this issue would be helpful.



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