SeaFoam available at Napa auto parts, price $6 a can.
How to use it: feed slowly into one of the vacuam line going into the cylinders (preferred using the PCV line). Use about 1/2 to 3/4 of the bottle being careful not to stall the car. At about the 1/2 pint mark you will start seeing smoke coming out of your tailpipes at idle. Once fluid has been sucked into the engine. Turn off engine for about 1-3 hours, the longer the better. Start the engine and begin the revs… watch the GIGANTIC smoke
Take the car out for a spin, and WOT the baby on the highway to clear out any leftover carbon from the engine. you should feel results in power, torq. and gas mileage
To clean carbon and varnish deposits from the tops of cylinders and the backs of intake valves, add 1 oz. Sea Foam to each gallon of fuel. Sea Foam will slowly re-liquefy the varnish and gum deposits that hold carbon together.
To remove carbon and varnish deposits more quickly, Sea Foam can be induced directly into the combustion chamber via the following method. With the engine warmed up and running, SLOWLY POUR 1/3 to ½ can of Sea Foam down the carburetor throat or into any main manifold vacuum line that DISTRIBUTES EVENLY TO ALL CYLINDERS. Note that some newer induction systems, like those found on Vortec and Subaru “H” style engines, do not have any vacuum line that distribute evenly. Consequently, this process should only be attempted by technicians with a comprehensive understanding of the engine’s induction system.
Once the product has been applied, turn off the engine and allow the Sea Foam to heat soak for a minimum of 10 minutes. At this time, Sea Foam will dissolve the varnish deposits that hold carbon together. After allowing the Sea Foam to soak, restart the engine in a WELL VENTILATED AREA as exhaust will be extreme for a short time. Drive aggressively for 2 to 5 miles to allow all the atomized carbon to be safely expelled from the system.
Performing a Sea Foam Engine Treatment on a Fuel Injected Engine
Begin by parking the vehicle in a well ventilated area. Locate a vacuum line that you are certain DISTRIBUTES EVENLY TO ALL CYLINDERS. On many vehicles the easiest option is taking the vacuum line from your brake booster PCV. (See notes about special situations such as the Vortex or Subaru H style engines.) If you are not certain, contact a certified technician.
Start the engine. For automatic transmissions, keep the car in PARK. For manual transmissions, put the car in neutral and apply the parking brake. SLOWLY POUR 1/3 to ½ can of Sea Foam Motor Treatment into the vacuum hose, while at the same time revving the engine to about 2000 RPMs. You will begin to see clouds of white exhaust from the tailpipes. When you have finished pouring, turn off the engine and let it sit for at least 10 minutes.
Now start the vehicle again. Drive it aggressively (but legally) for about 2 to 5 miles or until the white smoke is no longer being produced.