I know this is a Maxima forum but thought Max owners would like this bit of information. I kept reading how cleaning the throttle body on the Max helped cure the check engine light and poor performance with the Max. Well, the "service engine soon" light came on in my '97 Plymouth Voyager van and I ran the codes and "code 32" MIL (malfunction iindicator) light showed up. When I looked up that code in the shop manual it gave 2 choices. EGR (Exhaust gas recirculation) solenoid circuit, and EGR system failure.
Since my van has 125,000 miles I thought I would try to clean the throttle body and see if that fixed the EGR problem. It did. No more "service engine soon" light.
I guess the moral of this story is keep your throttle bodies clean.