Try a coarser grind. The finer the grind, especially with dark roast, the more "burnt" flavor will be there. Use a burr grinder not a chopper or typical cheapo coffee grinder thats just a spinning blade. A burr grinder will make consistent sizes whereas a chopper with a spinning blade will not. The smaller chunks will burn while the bigger ones don't fully release their flavor.

Your grinder is the single biggest bang for buck improvement you can make for your coffee experience. It's more important than the coffee maker or water you use. Some might argue it's generally more important than the beans themselves. A good grinder can at least make shit beans taste okay. A shit grinder cam make the best beans absolutely horrid.