I thought I'd post an update:
Starting around Halloween the "Check Engine" light came on while my girlfriend was taking the kids to school. Attempting to help me out, she went to Auto Zone for a free code scan and got P0172 from the employee. They also cleared the code, so I waited to see if it'd come back.
Sure enough it did. Having a scanner at home I saw P0172 and P0175, which is running rich on both banks.
Now, I had two things in mind with this. One is, the truck has a tune and runs on 91. The second is the weather is getting cooler out than when I did the tune. Perhaps the cool weather and tune had it running rich?
Either way, the MPG wasn't changing, there was no noticeable difference in how it ran to me, and emissions isn't due until the end of April.
Being too busy to care too much, I would clear the light and it would come on a day later or 2 weeks later until this past week.
Thursday night I move the truck to get in the garage attic and notice the light is now off. Since I leave the scanner in the center console, I assumed the Mrs. cleared it. However when I asked, she had not. She said the light extinguished itself.
A little surprised and relieved, I poked under the hood. While she was out earlier that day at the auto parts store I had her get some spray, electrical cleaner. I have to change the oil Monday and was planning on doing plug and wires as well to try and help the issue, but I wanted to see what I could try tonight.
First I pulled off the air filter. I was wondering if the readings/trouble code were caused by dirty air coming through to the MAF. I had heavily cleaned the filter in the summer (it was awful. Prior owner never cleaned it) but thought it cannot hurt to do again. Here is how it looked. Not too bad:
Next was the MAF sensor. I took it out and carefully inspected it. It seemed ok, but after hitting it with cleaner, I realized all the "rails" in it were black. Afterwards they were clean and shiny as so:
After reinstalling it all, I feel like the truck ran better on the quick late-night test drive, but I have a feeling that's just my mind playing tricks on me. Either way, no light so far...