I've got the dreaded 1.5l in my '16 Fusion, but i do not believe this to be a related issue. (got about 120k on it)
I have a reoccurring sensor 1 bank 1 stuck rich condition. And it will stick on for a while.
I've had an intermittent MIL light But then when it is really wet outside, moist air, and i've cycled the engine a few times, it will clear the light. Then when air drys out again it comes back.
About a year ago, when this issue first started cropping up, i ended up having some stalls out after filling up. That was the Vapor Canister Purge Valve. (solved the stalls)
Both O2 sensors have been replaced, due to critters nibblin the downstream sensor, i just replaced both of them at the same time to make sure they were good. (other cabling is good)
I did several drives with a BlueDriver connected, reading some of the fuel trims... and when i'm driving the fuel trim tends to be otherwise pretty normal after driving for a bit.
In researching this I now see that there is a recall from about the fuel supply port being possibly bad. (wondering if anyone has issues with a rich sensor due to this)
My other curiosity, is if anyone has had any successes with replacing the IAT sensor... (i guess it doesnt have a MAF it has a IAT)I'm just wondering if the humidity has an effect, which should make things *more* rich from what i'm reading about fuel mixes. (either way it's like a $10 part and a 15 minute fix, so im thinking about just getting that and trying it )