So I think i'm running into the first real issue with my 9-7x with 4AWD and the 5.3. Since it started getting colder her in MN the manually calculated MPG's have been dropping. Since I bought the car the average MPG for my identical drive have been about 17.9mpg per tank. The last two fill ups I'm now down to 15.1mpg for the same exact drive. I reset the DIC every fill up and it generally is hovering around 14.9 to 15.1 which are number's i've never seen before these last couple fillups which match the manual calculation. The car runs as it should with no issues or dash lights at all. Anybody have any thoughts on what could suddenly cause a 15% drop in mileage? I will also mention I keep all the tires inflated at 32psi as the 9-7 requires as I always have. Basically nothing has changed except the MPG's. The only thing I can possibly come up with is if the AWD is staying engaged all the time.