IF your starting it and running it(not driving) every other week, it still should be fine.... Letting it sit months or years at a time, is really when you want to start worrying about it....
Like Vile suggested though, run a good fuel system cleaner(Even just a tank or two of Chevron/Texaco Gas that already has the additives in it will work!)through it(Only run what is specific for your truck, IE don't run a fuel injector cleaner in a truck that has a carb, or vise-versus). Make sure to add it to a 1/4or 1/8th of a tank, and not on top of an already full tank(Yes it can be added to a half tank, but be sure to put gas on top of it.. Cleaners will mix and float to the top of the fuel, and it won't go to the bottom of a full tank until the level gets there)....
Personally I would also add a clear in-line fuel filter up by the Carb/Etc, to make sure your taking an extra precaution with stopping contaminates from the Carb/etc...
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