2006 chevy silverado 5.3 100,000 miles. there is no add ons on the truck. i just bought the truck and im going back to the dealership friday because they said they will fix the problem at no additional cost if they can find it. so i dont want to go there and they tell me they cant figure it out. i want to know 1 or more things it could be. i did a search on here and found alot of stuff about lifters or normail chevy tick. this is only when acclerating or punching the throttle. if i put it in park or neautral and rev it up there is no ticking. so i think it has nothing to do with the lifters. its sounds to be right under the motor and can hear it inside the truck.