I just checked the 2001 Mazda B3000 specs and found that the plus cab model has a 19.5 gallon fuel tank and the regular cab model has a 16.5 gallon fuel tank and that fuel economy on both models with the 3.0L V6 is rated at 17.0 mpg City and 22.0 mpg Highway or 19.5 mpg combined City and Highway average. At 19.5 mpg combined City and Highway average you should be getting about 320 miles if you have the 16.5 gallon fuel tank and about 380 miles if you have the 19.5 gallon fuel tank. So if you have the 16.5 gallon fuel tank and you are only getting 200 miles then your combined City and Highway average is about 12 mpg and if you have the 19.5 gallon fuel tank your combined City and Highway average is about 10 mpg. That is pretty bad and you would most certainly notice some severe driveability problems and I expect the check engine light would also be on. If you are not having driveability problems and the check engine light is not on then I suggest you look for a leak in the fuel system. Otherwise, I expect someone is siphoning your fuel or you are not fueling the tank full. But if you are having driveability problems then I suggest you scan for diagnostic trouble codes and maybe find a clue to the problem.
