I can swear by Seafoam. NAPA sells it I think at $6-7 bucks a can (if you got a AAA membership, NAPA gives you a discount!
This stuff isn't hype for sure. It works GOOD! Used it in my all my cars as regular maintenance and it keeps my engine on all my cars feeling like new. I recommended it to my other friends and they were impressed.
http://www.seafoamsales.com
To avoid all the attention, I would use this at night (as your neighbors might wonder what the heck is going on!). Good luck!
LOS