You have a VQ. There are no known issues with the harnesses or the ecu's in the 4th gen maximas. However, they have been known to have their coil packs go out for no appearent reason. Try hitting up www.maxima.org/forums or www.vqpower.com for some more insight. Being that the coil packs or easy to take off you can easily trouble shoot them by swapping them to different cylinders. If the no sprk issue follows the coil pack then you know what it is.
I highly suggest you find out how to read the trouble codes on the maxima as they are as bout as easy to access as you can find on any car.<--Check above links. Or you can do what i did and buy a code reader for 75 bucks and never have to go through the hassle of trying read the blinking lights and such. Plus you can use this on any import as well. Just one use will pay for itself.