Why does my 1997 Infiniti Q45 sputter when I've already changed the fuel filter?!
If you have already changed the fuel filter, the sputtering could be caused by a clogged fuel line or injector. Furthermore, the problem could also be caused by faulty wires or spark plugs.
What phantom said, plus it could also be other problems like the coil, timing needs adjustment, cam could be getting worn out (it is a 97), faulty fuel pump, clogged airfilter,