Most likely coils, but fuel issues or even the MAF sensor could give you problems like that. I have a 2001 Max, and the plugs in the rear are not that bad, you just have to use multiple extentions and a real plug wrench with the rubber "plug-grabber" in it. Also have a "magnet-on-a-stick" handy in case you drop anything.
Check your manual for recommended fuels, my brother had a 2000 Max and my 2001 both required high octane, due to compression. I don't understand why your VQ 3.0l engine would be different.
Also do a search for the shop manual, every once in a while it will be out there on the net in PDF form. The REAL Nissan manual that the company mechanics use.