I love it when added to the engine oil and run for the last 100-200 miles of driving right before an oil change. The engine in my car (VQ series Nissan/Infiniti v6) is known for the oil passages being quite small, and oil having a hard time properly lubricating the top end. As a result, even a small amount of buildup within the upper oil passages can lead to lifter tapping as the miles on the engine increase. The lifter tapping can be quite loud, but it only happens at idle when the engine is warm.

The first Seafoam oil treatment cleaned it up enough to make the lifter ticking go away completely, but then it started to come back by the time the oil neeeded to be changed again, so I repeated the treatment. Now I don't hear it at all, and I continue do Seafoam treatments as preventative maintenance every other oil change. One $7 bottle of seafoam does a little more than 2 oil treatments if I remember correctly. My engine currently has 175k on it.

I don't have any experience with spraying seafoam into the intake system or adding it to the gasoline to clean injectors and the fuel system.