2003 Ford Windstar

I find it hard to believe that there is that much carbon built up. It would have to be on one of the valves not allowing it to seal.

Listen, they make an carbon cleaner that is run through the engine while the engine is running. It burns with the fuel and is to clean all carbon from valves and the tops of the pistons. Ask to have that done. You will see a lot of black smoke from the exhaust when it is being done, but that will stop after some time.

If that doesn't help and the cylender still has 75psi of compression, then you have two choices. One is to perform a wet compression test. Pour a little motor oil into the bad cylender. If the compression increases, then there is a problem with the rings. If it doesn't, the problem is with the valves or a bad head gasket.

Let me know what you find or if you have other questions.

Joe