Good luck with getting any Fuel mileage with the stock EFI
My CrewCab did better than the 1/2 ton SWB reg cab 97 Sport 2wd I took it out of on fuel Both trucks tipped the scales at just over 5000# the 97 having 3.55's with a 31' tire got 16-17 Hwy the same engine with a carb spinning 4.10's with a 31" tire got 19 Hwy in my CrewCab
94 up tank won't fit at all It's way too tall