2012 mxz 6.0 engine

[Domingodrt]

Hi guys I'm a tecnition in S. A NEED SOME ADVISE busy with a 2012 mxz Malibu with 6.0 engine o2 sensor keeps bring up the service required once I cancel it on diacoms it gone test boat for more than an hr and runs well the next day start up after 10 minutes service required again cancel it with diacoms then no more service required iv changed all the o2 sensors cleaned manifolds replace fuel pumps and clean fuel system and replaced spark plugs any idea where too look thx in advance 

 

[kerpluxal]

Is the exhaust manifold cracked internally? This was my issue. To be more specific, I would get an open loop code on the diacom.  Water was getting to the O2 sensor from the cracked manifold. Is this port or starboard? From my research, the port exhaust manifold is common for cracking internally.

If this resolves, let me know where to send the invoice 

[dwc032]

There are literally 20 threads on this issue.  What code is it throwing?  I had the same issue come up on my 13 LSV, the light came on for years and I just kept clearing it or ignoring it. I changed both cats, all o2 sensors, and ECM.  I have no idea what was bad, but I put another 500 hours on it before I sold it and it never came back.  My guess is its bad cats or ECM. If you can't afford to throw parts at it, Id say just deal with it.  If you are mechanically inclined its not to hard to replace cats and super easy to replace ECM.  Bakes will have everything you need.