Not that as mine does it from time to time and its a 7spd auto.

Not sure but mine is 6mt.

I just noticed something on the car i noticed on a lot of other cars as well. Are you putting any pressure on the steering wheel when the rpm falls? It's a common incident in all cars with power steering. If you touch the steering wheel and put some torque on it, the power steering pump engages and applies fluid pressure. This increases drag and drops rpm down a bit for a couple of seconds before the ecu compensates by increasing the throttle opening and regaining normal idle speed.

My G35 did this every time I swapped intake manifolds or installed a plenum spacer.. Did exactly what you described. It would eventually go away after a day or two. I believe it was the ECU learning the new mod I had installed.

Could this be a factor for your car and it's mods?

EDIT: Just for reference I've went through 2 plenum spacers, and 3 different intake manifolds.

*** Update ***

added a techron bottle to my gas fill-up and the low rev dips are not a noticeable issue as of now, Seems my fuel system was kinda dirty, I will observe and probably do an techron bottle with every oil change from now on. I used to do this regularly on my old car but tough maybe I was exaggerating.... guess not.

Noticed this with my car tonight (2010 nismo) whenever I'm in a stoplight it dips below 1000 or around 500. AC was running on lowest settings. Should I contact dealer or not?

I had the same issue as the OP. The problems went away after cleaning the throttle bodies, and then performing the Idle Air Volume Learning procedure. After that, my idle rpm is steady at roughly 700. Hope this helps!

550rpm in normal for our engine.

I got that, too, when stock. With turbos and larger fuel pump, I can hear the fuel pump power sag for a little bit when it happens. Not sure if it is related.

good to know, thanks! :tiphat:

Reviving this post as I happen to experience the same problem. I haven't really noticed if related to A/C but I definitely have some, apparently random, idle dips of ~500rpm. What worries me is that a couple of times (one of which a week ago), the RPMs dropped like the engine was about to die and then revved back up to normal idle. I will keep an eye if this happens also with A/C off.

Stillen Gen3 CAI <= could be this. or a dirty MAF

was it doing it before your flash?

I don't recall it being a problem before the flash. Definitely not the RPM dip to 0. In fact I was thinking it could have been related to the tune.
Thanks for the tip, I will try to inspect the MAFs to see if I see anything wrong with those for now.

yah, if your maf is clean and if you can flash it back to oem for the time being just to see if it comes back or not, that would be a good start.

i donno, can you take a log and maybe send your file to uprev and see if they can pinpoint it on the map?

Yup. I can log. Good point I will try to monitor that, log and eventually send to UpRev. :tiphat: