Originally Posted by Disco Mike

The whole idea/ benefit of an induction cleaning is to, free up the air flow thru the manifold, and cut any and all carbon on the back side of the intake and exhaust valves. Has nothing to do with cleaning injectors, has some benefit to cleaning the plugs and inner chamber.
Seafoam is an OK additive for cleaning both the manifold and injectors, but nothing, especially at the amounts that they now recommend.
My all time favorite, although the most expensive, are products made by B&G, but for now lets just look at what I believe to be the only proper method.
First of all, I do a couple of things at the same time, I add a good additive to the tank, I do the induction cleaning and while I am waiting for the chemicals to be absorbed into all the old engine build up, I clean the t/body as well as the idle control unit.
My list of stuff needed would be, 2 cans of Seafoam, 1 can of carb spray, 2 feet of a small diameter vaccum line, a tooth brush,m pair of pliers and some paper towel. While doing this cleaning, I do not attempt to clean the crank case at this time, and even when cleaning it, there are far better engine flushes.
So, all that being said, find the smallest port of your manifold, hook the 2 foot piece if tubing to that port, get a pair of pliers, like a needle nose
, start the engine, get it to operating temp, crimp the hose that you have hooked to the manifold, with the pliers, put the other end of the hose into a full can of Seafoam and ever so slightly release just the smallest amount of flow thru the hose. You want to stretch out this part of the cleaning so it takes as long as a couple minutes to totally drain the can without stalling the engine.
Once done, turn the engine off, reattach the proper hose and now you start on the t/body. Remove the air intake hose to the t/body, look inside as you open and close the throttle plate, see all the crap in there on both front and back behind the plate, spray it real good, let it sit for a while, then using the tooth brush, scrub/ loosen up all the old carbon build up and then wipe it all out with your paper towel.
By the way, when you go drive your truck to blow off the smoke, take the can od Seafoam with you so if stopped by the police, you can show them you are not a gross poluter, just treating your engine.

Next, depending on the year and model, clean out you idle contoll unit and you are done.
Now of course comes the fun part, starting up the engine, which will fight you and smoke like hell. Turn the key, don't touch the gas pedal, just let the engine crank till it starts. Now, when no one in your neighbor hood is not looking go out and drive the crap out of it. I have to tell you, that no matter how hard you try, you won't be able to out run the trail of smoke that will last for at least 10 minutes.
Go home when done and just let it sit over night, in the morning may get a very small amount of smoke and then it is gone.
The engine will be much more responsive, smoother idling and perform better then it has in years.
A few side notes, the new directions on the Seafoam, give you different directions, mainly because too many people complained about the massive amount of smoke. Doing it per the directions will not give you anywhere near the same results.
I do it this way cause I don't have the metering valves to do it like we did in the shops, to me the pliers work well and it has to metered into the engine slowly, not dumped into a funnel and into the engine, this does nothing but waist a $6 can of additive.