Coyote Gen3 rough idle at start then smooth

[edwardb]

It's a little bit of a mystery to me that an O2 sensor issue would take out the whole bank. I can see the A-F ratio getting messed up, running poorly, MIL on with indicating codes, etc. But completely shut off? Honestly though I don't know. It wouldn't be hard to swap O2 sensors side-to-side and see if the problem moves. After you confirm the wiring is OK.

[Jeff Kleiner]

It's a little bit of a mystery to me that an O2 sensor issue would take out the whole bank. I can see the A-F ratio getting messed up, running poorly, MIL on with indicating codes, etc. But completely shut off? Honestly though I don't know. It wouldn't be hard to swap O2 sensors side-to-side and see if the problem moves. After you confirm the wiring is OK.

I think we’re seeing a “which came first, the chicken or the egg” scenario here. The sensor isn’t shutting down the bank of cylinders but rather the bank of dead cylinders is causing the sensor to be out of range. As for why one side of the engine is dead??? I don’t have a guess at this time.

Jeff