1998 Nissan Maxima Noise when starting

I also have 98 Max and have the same issue. When I start the car I get a grinding noise and sometimes it dies but it generally dies out. This generally occurs on cold starts (mornings, etc.) Also it seems that once it starts the RPM's are really low for about a minute, like 300-500. This doesnt happen all the time, but is fairly frequent. Just wondering if you had gotten any answers?

Thanks