Wich is the common problem I want to do a prevent service but I dont know how to start...

The most prevalent were the brakes and the noises. At this point tough, I think all of th 04s and early 05s have had the brake fix done. Search on rattles and you will find a few posts on noise reduction.

Here is one from November of 2004 that is the first one I an think of!

http://www.clubarmada.com/forums/showthread.php?t=173

the cost of gasoline.

1) warping front brake rotors
2) vibrations from the roof console, particularly if you have the DVD player
3) cracked exhaust manifolds

Recommend you take a look at the TSBs that Nissan has released for the 04 Armadas.

Keith

The cracked manifolds are with all year groups. Right around 60-80k.