recently i checked the gas milage on my 90 ranger,and im only getting 20 mpg,the truck has 147k on it,its a 2.3 twin plug,3.73 gears,5 sp,has no engine codes,nothing in memory,tires are 205/70-14,the truck runs well,tire pressures are up at 32 all the way around,plus the bed is empty so its not...