Cheapest HP, clean UR intake manifold
 

For $1.5 you can regain a few ponies! Here is how:

Remove the intake elbow, and spray carb cleaner on the throttle body generously to remove carbon buildup. 10-15 min job!

If you take the manifold out or just lift it by unbolting 8-10 bolts, you can clean the really dirty part of the manifold with lots of carbon built-up. This takes a few hours but the difference is night and day!

After cleaning, you'll benefit smoother idle, better low RPM response, no hesistation! You'll notice that the car will idle high for 50-100 miles but the ECU will adjust the idle so you shouldn't have to worry about it.

This should be considered a part of tune up! What a difference $1.5 makes!

Don't you need to replace the gaskets if you do that?

Mine was an FD and the upper manifold's gasket was metal. Metal gaskets are reusable so I didn't have to get a new one. If you are just taking the throttle body intake off, there is no gasket.

Should I use a brush or something? or just a rag?

Most of the carbon will come right off when you spray the carb cleaner. A toothbrush will work great as long as you make sure no bristle falls off into the intake. Same thing w/ rag. Make sure no lint is left in the intake.

Have fun w/ the job and you'll be on your way to a smoother ride!