Solve, using the correct order of operations, when $x=3$ and $y=4$. \[ 2 x-8 \div y \]

Step 1 ：The problem is asking us to substitute the values of $x$ and $y$ into the equation and solve it using the correct order of operations. The order of operations, often remembered by the acronym PEMDAS, stands for Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right). In this case, we first perform the division operation, then the multiplication, and finally the subtraction.

Step 2 ：Substitute $x = 3$ and $y = 4$ into the equation $2x - 8 \div y$.

Step 3 ：Perform the division operation first: $2x - 8 \div y = 2x - 2$.

Step 4 ：Then perform the multiplication operation: $2x - 2 = 6 - 2$.

Step 5 ：Finally, perform the subtraction operation: $6 - 2 = 4$.

Step 6 ：The solution to the equation $2x - 8 \div y$ when $x=3$ and $y=4$ is \(\boxed{4}\).