BANK TWO STUCK LEAN

[jcrmadden]

Check engine light came on this weekend. I made it to the parts store yesterday where they ran the codes for me. Verdict: Bank Two Stuck Lean. Now what?

[WWWPerfA_ZN0W]

I assume this is in relation to the oxygen sensors? Do you know the exact codes? That would tell you which one may need replacement. For example:

http://www.obd-codes.com/p2272

[autom8r]

If you have the time and the tools, swap your O2 sensors and reset your PCM. Drive for 10 miles or so and scan the PCM again. If the DTC moves to the other bank, it is most likely the O2 sensor. If the DTC stores the same code, then begin looking for a vacuum leak.

 

The fuel system may come into play, dirty fuel filter, injectors, etc. But I'd find it unlikely that the PCM would set a code for only one bank and not both, and that all 3 injectors on a bank would simultaneously malfunction causing a lean condition. Same goes for the air side, the MAF measures all the air flow going to the engine and not just to one bank.

 

Have you changed he spark plugs recently, or a fuel injector service performed? The spark plugs won't have a direct effect, but you need to remove the upper manifold to get to the plugs at the fire wall, if the manifold was not set back properly, you may have a vacuum leak. I don't endorse the fuel injector cleaning services either. But it wouldn't surprise me if the fuel system was damaged after performing one.

 

My money's on the vacuum leak.

 

Here's another link that explains it.

 

http://www.justanswer.com/ford/0uc68-dtc-p0174-system-lean-bank-no-2-mean.html

 

Good luck! Let us know how it goes.