What is wrong if your Impala LS 2004 3.8 ltr engine makes loud ticking noise when cold?

Of course a 11 year old car is not still under warranty. The noise you are hearing is the lifters starving for oil at startup. Change the oil and filter and make sure you are using the correct weight and a quality filter. Add 1 can of Seafoam which you can buy at most Auto Parts stores to the engine oil. Drive the car 1,000 miles and change the oil again. Add another can of Seafoam to the engine oil. This may help clean and quieten the lifters. If the noise you hear is more of a knock than a tick you may have a worn crankshaft bearing. The only cure for that is a complete engine overhaul.

take it back to the dealer it should be under warrenty still.