Same game up here, too lazy to drive the 9 miles to Costco, so the local Chevron got me...
My F150 mileage has slipped lately, we've been doing some analysis of a light load misfire, 5.4L V8, 2006, plugs are deep in the heads, 8 coils, boots feed them, maybe carbon trails, or a failing coil, but so far haven't been able to have it set the code, lock the data to tell us which cylinder.. So Wednesday it goes to my mech, pull 'em all, pin it down... Lots of interesting tech info out there...