There are two ways to use Seafoam for cleaning the fuel system. If you haven't done it in a while (say 20k+ miles) then do both using two cans.
You can pour in a can of Seafoam just before filling up with gas. It will remove deposits in the tank, through the lines, and the injectors.
You can also suck Seafoam into the intake manifold. The engine should be at operating temperature when doing this.
Instructions for sucking Seafoam into the intake manifold:
- Park the car outside a little ways from the house or garage. You don't want to smoke up the building.
- Remove a vacuum hose from the intake manifold and attach a section of vacuum hose to the intake about 18" long.
- Crank the engine. It may idle higher than normal but that is fine.
- Slowly lower the vacuum hose into the can of Seafoam and allow about 1/4-1/3 of the can to be sucked into the vacuum hose. It will bog down but don't let it die. Pull the hose out when needed to let the engine recover. Continue until you have about 1/3 of the can sucked into the engine.
Dumping Seafoam into the engine too fast could result in engine damage due to the pistons trying to compress the liquid!
- After you have 1/3 of the can sucked into the engine allow the engine to die or turn off the ignition key. Let it set for 15-30 minutes to give the Seafoam time to clean the intake and fuel system.
- Put the vacuum hose back on the intake manifold.
- After the time is up crank the engine back up. It might require some throttle feathering at first, so just keep it alive till it smooths out.
- You will most likely see a lot of smoke coming out the tailpipe. This is normal. as all the excess Seafoam gets burned away.
- Put the left over into the tank, if you have NOT already added Seafoam to it.
You should notice a smoother idle and better acceleration immediately after the smoke clears.