how long until my maxima (2000 gxe) is completely broken in?

i have 2900 miles on it and i feel that it lacks some power. could it be that i got a lemon, was too harsh on it when it was new, or it just isnt completely broken in yet?

 

2000 Nissans don't have a break in period. They don't use break-in oils, and they can be driven hard right off the showroom floor. However, after 20k miles is when the car is considered "broken in".