Use any line that connects to the intake manifold. If you remove the throttle body cover, you will see a vacuum tree with a couple of spare covered nipples. Attach a small line to one of the nipples.

Just remember, there is enough vacuum at idle to suck up the entire bottle! That will break your engine, or a wrist pin, so dip the vacuum line in the bottle and let the engine 'sip' the liquid as you repeatedly dip the line at about 1 second at a time. Read the instructions on the bottle! Pour the other half of the bottle in the gas tank to help clean the injectors.

Klaus
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Always willing to listen, just not able to take direction.