Last week I changed out an old, cracked vacuum hose and tightened, tweaked, twiddled, twisted, tuned and turned anything I could find in the engine bay.
Because this code is somewhat ambiguous, I couldn't "go after it" unless I wanted to spend time and money on it. Which of course I didn't. Never do. So I practiced what I preach, which is to start with the simplest, easiest, most logical solution attempt first.
In this case it was trying to find a simple vacuum leak, or one of the dozens of little connections that come loose in our 850 engine bays. I was lucky -- something I did took care of it. I don't know if it was the vacuum line or not. The next step would have been doing more research on the code, and might have led to a new O2 sensor. Not a difficult job, but $100 for the part.
The cracked hose was the Yellow hose here:
See this P0422 and other codes in our not-yet-very-helpful Trouble Code chart.
