
http://www.seafoamsales.com/
Seafoam is an engine cleaner found at most parts stores for $6 a bottle. You can use it in your oil, intake or gas tank. Here is a sort write up of what I just did to my neon. I must say it sounds nicer and gets better gas mileage now.
1. As planned, i put 1/3 in the gas, 1/3 in the oil, and the other 1/3 thru the vacuum line.
2. Do the gas and oil first because the vacuum line sucks it up real fast
3. To find the vacuum line: look behind your battery and you will see 2 electrical connectors. just below those connectors you will find the brake booster, the large black metal cylindrical thingy, you will see it. on the left front of that you will see a 3-way splitter, there are 2 smaller hoses connected to it, and then a larger hose, probably 1/4 to 1/2 inch in diameter, this is the hose you want. mine was on the left side of the splitter, but i dont know if its that way with all. pull it off and your engine rpm's will shoot up.
4. Slowly stick the hose into the can, if you stick it in too fast your engine will die. i only stuck mine into the can maybe an inch or 1 1/2". the engine will start to stumble, if you think it is going to die then pull the hose out a little. my engine never did die once all of the seafoam was gone so i just stuck my finger on the end of the line and it died. i let it sit for about 5-10 minutes and took it for a drive.
5. it did run like crap for the first 5-10 minutes of my little drive and it smoked a lot as well, but i was getting a lot of looks so it was fun... : ) The smoke is the carbon build up coming out. Do this every oil change and you will see a good difference.
*** Once done in the oil it is important to get an oil change to clean out all the particles in the oil and change your spark plugs***