usadaytrader

I now have 90k miles on a 4 cyclinder 2005 Tacoma. The valve tap started at 60k. It will go away after every Seafoam treatment. It makes its way back after awhile. I've been using Chevron with Techron on a regular basis. Anyone have any ideas on excessive carbon buildup?

William

Are you talking about carbon buildup in the combustion chambers? The reason I ask is because you mention valve tap, and what I normally hear associated with carbon buildup refers to the combustion chambers. The two have nothing in common.

Assuming you are talking about carbon in the combustion chambers, there is an easy fix: water.

What you do is get the engine up to normal operating temperature. Find a way to access the intake tract, preferably at the inlet to the throttle body. Get a cup full of cool tap water. With the engine running, rev it up and SLOWLY pour the water down the intake. As the engine sputters, give it enough throttle to keep it running. Don't let it stall. If the throttle body/intake tract is located where you can't pour into it, get a squirt bottle. You want to make sure the water isn't poured in the intake tract where it will pool up in the bottom of the intake. Revving the engine fast enough will help prevent that.

The water will hit the hot carbon and blast it away. As long as you don't pour too fast, there should be no issues with you using water.

The ONLY problem I have ever had with using water was on a Honda lawnmower engine. After using water, it quit and wouldn't start. When I removed the plug, I saw where hard carbon deposits had been knocked loose and had clung to the plug tip. When I replaced the plug, it ran better than it ever had before.