When using Berryman B-12 CHEMTOOL TOTAL COMBUSTION CLEANING KIT (part #2610), the hose should be attached either to the brake booster or in place of the PCV valve. For a product that connects directly to the fuel, see B-12 CHEMTOOL FUEL INJECTOR CLEANER (part #s 1120 and 1126). Here is a link to a YouTube video that might be helpful if you are using part #2610. https://www.youtube.com/watch?v=v4FRqRvGCBs&t=3s Let us know if you need further assistance...Thanks!