No this isn’t coal, it’s carbon buildup. The engine wouldn’t run and it wasn’t able to breathe. So a new intake and carbon clean out resulted in this engine running much much better.
We do encourage on certain makes, models and engines to incorporate carbon cleaning as preventative maintenance to assist in avoiding conditions seen here.
For more information about this a new intake and a carbon clean out and how it can help you, give us a call at (978) 388-1288.