My roommate is a strong disbeliever in additives. I bought some fuel injection cleaner and I was wondering if that's a waste of time? Does that crap actually work?

 

If your fuel system is perfectly clean then it's a waste of money.

What kind did you get? Some stuff seems to work better than others, if you need it at all. I certainly wouldn't use it every tankful. Some people use it every oil change, Iuse it less often than that.

 

I'm not a great believer in injector cleaner for Hondas; probablyseen less than five bad/plugged injectors thru the past 20 years.
I am willing to go out on a limb and say that a 'top end' decarbonizer could be a benefit after 100-150k miles. The motor-vac systems do a pretty good job of getting crud off the valves.