2011 ss 190 fourwins 4.3 sluggish

[482nova]

our 2011 fourwins ss190 with a 4.3 gm v 6 started to use a TON of fuel. sluggish getting on plan and way down on speed. new plugs, cap and rotor, new fuel filter, new thermostat no change? starts perfect , idles fine. plugs very black this is a fuel injected motor. bought brand new so i know the boats history IDEAS ? thanks in advance

[Little boat that could]

If your getting black plugs and black smoke check coolant temperature sensor or restricted airflow

[Euroski]

should be a easy diag once a scanner is connected by a knowlegable shop which sure beats throwing parts at it and guessing?