theres a cap looking thing, but no distributor underneath. but it's direct spark like most new cars.
my MAF had weird effects on my MPG even before it had negative effects at idle. depending on mileage, i'd check that also. swap MAF's from your GF's car to test it maybe? just a thought.
what tire sizes are on both cars? wider has more drag/friction fwiw. lighter wheels would act similar. but thats a stretch having seriously different sizes or weights of wheels between the 2 cars. but is possible, just not probable.
sticky drum brakes in back? mine would stick but make no noise on my old L sedan. noticeable usually in reverse when drum sticks from sitting, then suddenly pops free.
--keith