My lifters are sticking a little that's the reason it's clicking and was told to buy Sea Foam Auto Marine Fleet. I read the bottle but doesn't tell me how to do it. I was told to add 1/2 of the bottle (473 ml) to the oil crankcase and the other 1/2 into the gas tank. Is this correct? Do I need to run the vehicle after I put it in?
Lifters that are noisy are not pumping up, and that is usually due to low oil pressure. I'd have that checked first with a mechanical pressure gauge.
I don't know how you expect a chemical in the gas tank to help internal engine parts but of course you're going to have to run the engine. Otherwise the stuff will just sit in the tank and do nothing. What it will do when the engine is running is to clean and dislodge varnish buildup in the injectors. Some people report their engines run better. Some people run into plugged injectors that need more expensive service. Most people don't notice any change.
Many people have been satisfied with the results from adding this stuff to the oil but the chemicals are not the same as the detergents, seal conditioners, and corrosion preventers in engine oil. If you add any "mechanic-in-a-can" to the oil, have the oil changed within a few days unless the instructions specifically say it's okay to leave it in.