3.4 Noisy

[Soleau]

I got an 3.4 engine that rattle when the engine is cold but the as he get warmer, the rattle seems to fade away.

 

I've read that the problem came from a cylinder.. It says: "abnormal wear of a piston or cylinder"

 

I'm wandering if it's critical to go at a reseller and try to trade my truck for an other one , or if it's an minor problem and I can ride it for another 100K miles???