I used to do this about every 25k miles on my 1993 Camaro Z28 (LT1) to clean the motor out and get rid of carbon build up and it always seemed to help it out a lot. If you aren't familiar with the process you pour one can into your fuel tank, 1/2 a can into your oil, and the other 1/2 of that can goes slowly into a vacuum hose (which the brake booster was the easiest on the Camaro) until you have about 1/4 of the can left and then you dump it in to kill the motor and then let is sit for about 20 minutes before running it. Then you use the Seafoam Deep Creep to spray into your throttle body. Also of note is you run the gas tank almost to empty and you want to be sure you change your oil within about 300 miles (and I'll tell you the first time you do it that oil is blacker than black).

Has anyone done this on a 4.3 or can you can think of any harm it would cause? I know the LT1 inside and out but the 4.3 is still fairly new to me so I don't want to mess anything up; just looking to restore a little power, maybe get a little better MPG, and just deep clean the motor now that is has almost 113k on it.

 

Plenty of people on the forum have used it in their Blazer. It works like it does in other engines.