[30 Closed Cab PU]

I do not know your experience level on As, so excuse me if you already know this info.

When reading the plug only go by what the ceramic insulator looks like. It is not uncommon for the rest of the plug to be black/slightly sooty. Look for a nice tan color, clean/pure white is too lean, black/sooty is too rich. When I first got my truck, had difficulty believing it was OK to have black and soot on the plugs with a tan insulator - was too used to modern cars, especially cars with electronic ignition and fuel injection.

Perhaps post a picture of your Plugs?