Does it tap faster when you rev the motor?

 

change your oil, oil breaks down even though it doesn't have mileage

 

Already!! It's only been a year!!

 

Well let's assume it's not a valve tap. How about a serpentine belt tensioner or a very small exhaust leak. I've had both on a Chevy truck and would have sworn they were valve taps. The exhaust leak would only show up when it was cold outside but would disappear when the truck warmed up. The belt tensioner was a common problem on several GM vehicles but I thought they had that ironed out already. Anyway, just a couple ideas. Either way, it should be warranted. Good luck.

 

YOU'RE STILL UNDER WARRANTY, TRY TO BLOW IT UP, I BET IT WON'T

 

I'm going with exhaust leak, loose collectorbolts at the pipe flange. The exhaust manifold head bolts rarely get loose, but it has happened. Crud, you could even have a crack in the pipes somewhere. Hello trip to the dealership. [:'(]