seafoam is ok as far as what you can buy at discount retail or diy parts stores. if you want a really good cleaning try 44K by BG. you can only buy it through a shop. they also make a complete fuel induction system cleaning kit, but it too is only available through authorized shops. it is not cheap but it is well worth it. i regularly use 44K in all my vehicles and i do a complete fuel system service about every 30k miles or as needed if i get running issues.

if you use this type of product on a regular basis and stick to a good maintenance schedule then underlying damage isn't usually an issue. if the car has not been maintained a good cleaner can actually cause problems. i have seen this more than once but it only took the first time for me to learn the lesson. i sold the service to a woman with an 83 or 84 buick regal. the car looked like it had never had a service of any kind done to it during its 140k+ miles. the service went fine, clouds of white smoke billowing through the shop as the BG did its thing. she had not been gone from the service department 10 minutes when she called the shop. car just quit while she was driving. turned out that the fuel pump had died. fixed that but it set off a chain of part failures. shop manager finally sent her packing. each new part cause another old one to fail. so...if the car has not been taken care of be wary of trying to fix running issues with a cleaner.

 

I use seafoam often, even on the motorcycles and yard equipment.

I like to use seafoam in the oil before an oil change, I'll drop a half can in the oil and drive for about 100 miles, then drain the oil.
The first time I did that I started to get a little back pressure when I let off of the pedal, and I never get a valve knock when changine my oil (I also use Mobil 1 and M1 filter).

I use it in the fuel when I start hearing my injectors, or the fuel pump starts getting really loud... it seems to make it quiet.

I suck it up through the brake booster hose to clean the engine out, I started to do this out in the middle of nowhere.

First time I did it I lost an 02 sensor, I figure it was on it's way out anyways.

 

cool, i have yet to seafoam mine, but i think i should, casue i just hit 70k and need and oil change