Gas Mileage
I've never heard it referred to that way either, but since the job of the filter is to cleanse the oil of particles that cause friction, a lousy oil filter would contribute to increased fuel consumption. I don't know that it would be this noticeable just from that, but would always get at the minumum a "premium" filter and not just the cheapest one. I've never seen any test results as to which are the best.
Sammamish, WA
Epilog Legend 24TT 45W, had a sign business for 17 years, now just doing laser work on the side.
"One only needs two tools in life: WD-40 to make things go, and duct tape to make them stop." G. Weilacher
"The handyman's secret weapon - Duct Tape" R. Green