We have an 06' SAN with the 6.0 L engine, lately I've noticed it's sluggish when accelerating and the top speed is way under the norm. There is also a strong gasoline smell in the exaust. Last weekend while cruising the engine kicked over to full power randomly for the last session. This weekend it's back to the sluggish feeling. We're checked the flame arrestor for clogging but nothing changed. Does anyone know anything else to check before actually bringing it to the dealer? Any help would be awesome, thanks.