I have always used cleaners in both my z and my porsches and vws.
I mention the german cars for the one reason that the nissan injection is a licensed reproduction of the Bosch injection system used on 944's 911's Golfs Jettas etc
I have had great luck with all of these by using Berryman's B12 to me it works better than Berrymans FI cleaner.I spent several years working on nothing but european cars and never had a single probem using these products. In fact it is time to run some more through my 280zx.
Luck to all
helowrench