If the EGR valve in your Honda gets clogged with carbon, you will feel the effects when your vehicle is idling at stoplights or while sitting in traffic. If your EGR valve is clogged, you don't necessarily have to replace the valve. It is possible to remove the EGR valve from your Honda's engine and clean all of the carbon deposits from the valve. Cleaning your EGR valve should make your Honda idle more smoothly.
Unhook the car battery. You should always unhook your car's power source when working beneath the hood.
Remove the engine cover if your Honda has one and find the EGR valve. The valve location will vary between vehicles. It is toward the front of the engine on the driver's side for most Hondas. The owner's manual will have a diagram to help you find the exact location of the EGR valve.
Remove the EGR valve from the engine. In a Honda, the EGR valve will have one electrical connection to the engine and may also have 1 to 2 hoses attached. These connections will likely be held with retainer clips that will just need to be pressed to release the plug. Hoses may be held in place with screws. The valve will also be bolted in with 1 or 2 bolts. Use a socket wrench to take the bolts out and you will be able to slide the EGR valve right out of the engine.
Look for holes in the valve. If there are any holes in the EGR valve or weak places that look as if they are about to become holes, you should replace the valve instead of cleaning it.
Clean the valve with carbon cleaner. Carbon cleaners can be purchased at auto stores. Just turn the valve upside down on a stable surface and fill it up with cleaner. Let it soak in the cleaner for at least 8 hours.
Use a wire brush to remove any visible deposits left on the EGR valve. After soaking in the cleaner, any deposits should brush right off.
Replace the EGR valve. Put it back exactly as you found it, hook the wires and hoses back up and bolt the valve back into place.