nickwu 
2009 Nissan Altima Sedan 2.5 4dr Sedan (2.5L 4cyl CVT)
Noisy below 50 degree
 It is the worst car I ever bought!. If below 50 degree, start the car and it will sound like motorcycle and no power. I have to drive it for 3-4 minutes than it quite down. Nissan says it designed like that and meet the specification. My 2004 150K mile Toyota is better than this car. Service is absolute the worst too, they told me to install a remote starter to warm the car so it would be less noisy. But Nissan USA told me it was wrong, and won't fix the noise issue, you need to drive it to make the lube "go through every places" . I lost $400 right their! They stated all Altima car like that. Battery died 4 month later. Already did three warranty services and two recalls. Last Nissan!