If it were anywhere nearly like that, farmers would have used gasoline to blow stumps out of the ground instead of dynamite.

The perfect fuel to air ratio will allow gasoline fumes to burn at its most rapid rate, however that is no where near the rate of expansion that a pressure wave off a stick of dynamite propagates.

You also have to remember that you have to have all that air inside a gas tank for it to be at just the right ratio to burn this way, which is normally not the case with a closed gas tank.

I've seen plenty of auto races where cars have caught fire, some of them in classes without fuel cells containing foam cores and they do not explode, they just burn like crazy. If there ever was a perfect environment for a gas tank to explode, it would have been all the times I've seen cars burn down to nothing on those occasions. Not once did I ever see any of them explode. Exploding fuel tanks are a movie illusion, not something that happens the way it is depicted.