Purchase a length of 5/8" OD Tube for Hot/Cold Water, a Nylon Elbow, 1/4" NPT x 3/8" ID, and a Plug Hex-Head, 1/4" NPT
The Nylon may be substituted with Polyethylene, but do not use Brass.

Cut the Tube to fit the inner diameter of the Plenum plus 1/2 inch.

Tap both ends of the tube with a 1/4 NPT, 18 Threads per inch Tap.

Drill 4 or 5 evenly spaced 3/16" holes into the tube, making sure that all of the holes are lined up.

Screw the Hex-Head Plug all of the way into one end of the tube.

Screw the Nylon Elbow into the other end.

Put a mark on the Nylon Elbow in line with the holes.

On the Plenum of your vehicle (that's the Air Tube that runs between the Air Filter and the Air Intake), drill a 5/8" hole, but only on one side. Drill the hole after the Mass Airflow Sensor, about 3 to 6 inches before the Manifold if there is room.

Insert the Spray Tube into the hole until it touches the opposite side of the Plenum, making sure that the small holes in the Spray Tube are facing towards the Intake Manifold. If any of the 3/16" holes are not fully inside of the Plenum, then the Spray Tube will need to be shortened. Once the length of the Spray Tube is satifactory, then put a thin bead of Silicone Sealant around the tube where it meets the Plenum.

On the opposite side of the Plenum, drill a screw into the Hex-Head Plug to hold it securely in place.

Attach the 3/8" Gas Line to the Fitting.