timing belt

k i dunno y my car does this but sometimes, when the engine's cold, when i start the car something in there makes this loud scratching noise and i dunno wat it is...some people say that it's the timing belt...so that's my only idea that i got about that...how bad is it? do i have to replace it asap?

We have timing chains and they're quite durable, doubt you're having a problem with the chain.

If it goes away or only lasts a few seconds I doubt it's the timing chain...if that was scraping (it might scrape a worn chain guide, if Maximas have them) it probly wouldn't go away. I'd have to hear it, I can't really diagnose it over the net.