Yea just took the G35 to the dealer AGAIN for the same problem
The first time, it was sputtering while cruising for about 2 seconds every mile or so, and sometimes had a rough idle. Well lucky me the light came on so i ran to the dealer and they "resetted" the ECU and the car ran great !!

1 week later ... last night does the same .. i went to down shift to switch lanes
and the car lagged to get power then eventually went, later I start to feel the same symptoms, sputtering while cruising, this morning i wake up to go to the dealer, the car just wanted to die when i first started it up ... so ya now its at the dealer and if they cant get to it today ... most likely monday =l

I am lead to believe it has to do with water somewhere, because the first time it happened was when it was raining earlier that day, and yesterday it happened right after i washed my car ... what could it be .. ? btw the car is stock !

 

found out the problem .... ugh so mad
so apparently the previous owner of the car totally forgot what "maintenance" was
It was that there are some butterflies that use oil to work and the oil was so ewww that it was damaging them, and building up pressure making it sputter =[

intake filters were blackkk

by the way only had the car for almost 2 weeks

 

^ thats the most likely cause, im guessing youre talking about dirty Throttle Body valve, next time you can try to DIY from the section and save a few $$.

Did they do this for free this time since you just got the car, or u got the car elsewhere?

 

well i had no idea what the problem was, so i took it to the dealer, they are doing an oil change, new air filters, and new valves, costing me 200 bucks =/
at least i now know, for next time
trust me i usually do things myself but the car is new and dont wanna mess with something im not comfortable with just yet

 

they are replacing the TB butterfly valves? why? my suspicion is that they are just going to clean the valves but i could be wrong, if they do replace them along with oil change and filters is an ok price considering you are getting this done at the stearlership!

Im guessing its too late to take your car elsewhere and save a few $, so i hope the $200 lesson is worth it in the long run!

 

Pcv valves were replaced
And they did an ECU update for the cam sensors

 

^ah ok, as long it all works out in the end