Running Issues

You have given precious little info to go on. Engine? You think maybe you could tell us about it? How it's built? Is it stock? Does it have performance parts? Has it ever run well? You know. Important information that can help us help you. I know if I wanted help with something, I would be giving an information DUMP. Throw us a bone here.

What I see from that one plug is an engine (whatever it is) that's runnin pig rich.