What is the easiest way to clean the throttle body and the fuel injectors? Is there any sort of spray or something that I could use? Also, what's everyone's opinions on oil and fuel additives? Do they really do anything? The reason I ask is 'cause there's this stuff called Restore USA that supposedly restores lost compression. I've heard it's good, but I don't really know. Also, do the fuel additives that supposedly clean fuel injectors really work?