i just saw the, " ENGINE SERVICE SOON" or some crap like that on my gauge.
what should i do now? go to dealer or i ehre a way i can get rid of it myself?
by the way, does this mean that there is something wrong with my engine>?

 

Just bring it to Nissan and have them pull the code. Its probably the damn catalyst error that scared me.

Usually the MIL light comes on when it sees a faulty O2 sensor or it thinks it does...

 

Yep - go to dealer if you still have your Max under the waranty.
I had the same problem as many ppl here http://forums.maxima.org/showthread.php?threadid=89345