k i got a ford ranger with the rim and tire the rim is a 14inch stock rim and the tires are 225/75R14 k so if i got a 16 inch mustang rim and put 225/75R16 the tire hight and all the way around the tire would be the same except the rim would be bigger right well heres my question which one is going to weigh less ,,, my concern is my gas mileage

You'd just have to weigh them yourself probably. One issue though is 'rotational mass'. I'm no expert on it, but from what I understand, the further out the weight is from the center of the wheel, the harder it is to turn. So basically, even if they both weigh the same, you will 'theoretically' get less mileage from the 16's. Besides, mustang rims have a horse in the center...