So I decided this weekend im gonna Seafoam my 99 4.6 4x4, it has 86,xxx on it. theres no big reason why im doing it, just a small weekend project (gotta change oil anyway) and basic maintainance. I figure ill do 1/3 in the tank, 1/3 in the oil, and 1/3 in the brake booster like most. let it sit for 10mins then go out for a nice 10-15min cruise come back and change the oil and spark plugs (cuz i havent done that yet and have been meaning to.) So thats about all there is to it right? The only downside is that ive heard some ppl do it and there engine runs worse than b4, or gets hydrolocked, and my truck manual said that oil additives are dangerous. so is there something i should be worried about while doing or any other info i should need to know. thanks.