Truck Repair: engine rattles, unleaded gas, phenomenon

Question
n14 plus the engine makes a noise that sounds like a gas engine spark-knock fron unleaded gas. i'm lost on this
please help me if you can

Answer
Dennis'
you need to provide more details of this phenomenon for proper troubleshooting. Example, is the sound coming intermittently, is it accompanied with black smoke, does the engine vibrates when this happens. is your vehicle due for service e.t.c.
Thanks.