P0172 and P0175 ONLY when 30's or colder?

Sincoln

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Car is actually a '99 Continental, but being this area is more active and the engines are similar enough, figured it was worth asking in here instead.

When it gets into the mid 30 F degree temp range, it'll pop a P0172 and is sometimes complimented with a P0175. If temps are in the upper 30's or warmer outside, it seemingly won't pop the code. Code appeared once last winter (usually have a dedicated winter beater so never drive this in the winter until this season) then never appeared all summer. When it reappeared during winter driving, remembered it from last year.

No other warnings, codes, nor drivability issues. Exhaust pipe is NOT sooty. Engine temp is normal and not overheating nor running too cold. Still e-checks when warm out. Went ahead and replaced the coolant temp sensor anyways (mounted in a similar location as the Mark VIII's) and no change. Plugs have barely 9k miles on them.

I'm currently stumped as everything seems to work. Is there another sensor the computer relies on to read ambient temps to make adjustments? Is this an issue on Mark VIII's? Had a '96 Mark and it never had any issues during 62k miles of ownership. Have noticed the outside ambient temp readings on the climate control gauge might be off by a small amount at times vs. what the phone is saying for the area. Other day it was showing 30 F outside on the car's readout but it was still raining out and not freezing rain yet which would suggest a discrepancy. Phone was still showing around 35 degrees. When it eventually started changing to snow, car still showed 30 F.

Any ideas? Does the ecm use the sensor in the front, behind the bumper (pretty sure that's it) for fuel trims?
 
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