Good quality fuel in the tank is the best additive. VP or Sunoco mixed with pump gas works great. Amsoil and VP make good additives.My set-up is basically brand new. When I swapped my engine into my other car, it had maybe a few thousand miles on it. At that time I noticed some of the intake valves had a little build up. I suspect the gas on the base is just cheap and the lowest amount of detergents. I'm not looking to clean a highway beater.
Trade name "TECHRON". I used it in the engine test lab I worked in. Excellent stuff.Actually there is a product that is specifically to remove carbon deposits in combustion chambers it’s called techroline by chevron. I worked there 40 yrs and the science lab was on our refinery premises so asked one of the scientist working on it how good it was. He showed me some pre and post treatment data that was pretty damn impressive. It’s an additive added to each tank so it happens over a considerable legnth of time but it works great!
Great stuff. I haven’t seen that in over 15 years. I remember the oil and spark plugs needed to be replaced after use.