basically they're just using a top end cleaner, perfer seafoam to be honest as i have seen better results than from the GM branded cleaner and it only costs $7~ per can, usually i use one can but due to your larger engines than the 6 in my car i would suggest using two cans, one full can in the fuel tank with a fill up (or atleast a half tank fill) and then around 1/3~1/2 a can in your oil and the rest in a vacume line, i use the PCV hose (REMOVE THE PCV!!) and just have someone on the gas or give it a lil throttle by hand as you allow the vacume from your engine to suck up the seafoam, once thats done shut your engine off and wait aproximately 15 minutes before restarting
it should be noted thatsmoking is normal, if you have a higher mileage car sometimes it can turn into a smoke show but its normal, just make sure your slowly allowing the vacume to pull the seafoam from the container and never fully submerge the hose
its kinda like you would do to steam clean the combustion chambers but its a lil safer with seafoam as its combustable and theres a lot less of a chance of hydrolocking your engine
