getting the vacuum line through the grommet in the firewall. Take a huge nail, about 1/8" diameter, and sleeve it with a thin straw. Then with the tip of the nail poking out of one end of the straw, push it between the cable and the inside of the grommet. Once the sleeved nail is through, slide the nail out of the straw, and feed the vacuum line through the "doorway" you've created. Once you feed it through, you can remove the straw.