All you have to do for seafoam at least for a civic is go to any Autozone or Discount Autoparts store and buy a $5 dollar bottle of seafoam and the cheapest spark plugs you can buy. Go home, let the engine cool and take the old spark plugs out and put the new shitty ones in. Pour a 1/3 of the seafoam into your oil, a 1/3 into your gas tank, and a 1/3 into the intake (with the car on). Let it sit for about 10-15 minutes and then drive the car and smoke away. Some cars will smoke more then others depnding on how rich they're running, gas being used, etc. When your done with the seafoam make sure you change your oil and put the old spark plugs in. I didn't mess with my o2 sensor and haven't had any problems. Hope this helps. If you need a more exact DIY PM me.