I have a 04 g35 sports coupe and recently changed the intake from stock to K&N cold air. Once I changed the intake i noticed the idle started to fluctuate and kinda spurge. I was told that it could possibly be the MAF sensor, throttle needs to be cleaned or the idle may need to be re-learned, so i took it to the dealer and did just that. Bought a new MAF, cleaned the throttle body and had the dealership update and re-learn the idle. Once i got the car back the check engine light was no longer on but the car was still running very lean and the idle was still fluctuating. I then had my local mechanic smoke the engine to see if there was a vacuum leaks but came back without any.. im now stuck on what to do next.. does anyone have any suggestions or ideas?

 

I know someone with a 350z that had an issue like this, but they had a short ram intake with no heat shield and it was sucking up hot air thus causing the idle to fluctuate.
But with a cold air intake I dont know what would cause this issue

what is the idle RPM like?

 

is that the only mod done to the car?? when these cars run leans the ecu actually goes and dumps as much fuel as possible into the car. had this problem on my car before getting a tune and now everything is golden!!

 

Yeah no other mods have been performed just the intake. The RPM are fluctuating in between 200 and 300. My mechanic told me the same thing about the fuel being dumped in at a high rate. So you suggest getting it tuned?

 

with it running the way it sounds i would suggest it. do you plan on modding the car out any more?? cause if so buy all ur mods. put them on, then get tuned the next day

 

It's not lean. See my reply in the intake section (to your identical question)