[Christ]

Use the vacuum line from the brake booster... it fits into the top of the can, usually, and make sure you dump out 2/3 of the can into something else first. (you only need 1/3 of the can in your engine).

Fuel based "engine cleaners" do not work, simply because there are already so many detergents and additives in your fuel that adding a little more is like adding soap to the suds on your hands.

The other reason they don't work is because so little fuel gets injected at such a high temperature into your engine, that it's nearly completely vaporous by the time it actually gets to the combustion chambers... vaporous cleaning supplies do next to nothing, unless they're steam.

Another thing you can do to clean out your engine (that actually works) is just a light mist of water into the intake pipe, before the filter. It's just like steam cleaning, and will eventually loosen any crap that's built up in your engine.