Hello, I have a 2011 G37 and have been having this high idle issue, and it is starting to get annoying. When I start the car it will idle per normal no issues. When I am coming to a stop you can feel the downshift from 2nd to 1st and it will send the car forward. I have to really get on the brakes or the car would want to go. When at a stop sign/light the idle will be at 600rpm then start raising to 900rpm and stay there. I did what many would do and it was to clean the MAF and throttle bodies with the pedal dance to reset. After doing this the car actually idled fine with no issues for a week. I was merging onto the highway and did a WOT and then the issue started again. Came to a stop and idled at 600rpm and rose up to 900rpm.

I have read many forums from 350z, 370z, g35, and g37 that had this issue, but they are really old posts and the OP never gave an update. So if anyone else has had this issue and found a fix please let me know.

 

Sounds like a vacuum leak. May want to check all your rubber hoses connecting to your intake manifold.

 

Mine does this on occasion to..mine started after the retune after going forced induction too..did you do a fuel return? I'm thinking maybe it's something with the venture that wr have to drill when we do fuel pump and fuel return...if you ever figure it out please list an update.
my tuner has no answer for it either..if sent him data logs and everything in the tune is spot on but it still does it..mine isnt all the time like yours though

 

yes I have checked for vacuum leaks. Like when the car is cooler it doesn’t do it but it only does it when it has finally warmed up which is the odd part. I have let it get warmed up even and sprayed brake cleaner around the intake area and nothing. Does not spike in rpm or any of it. I also have stock air intakes. I also changed the PCV valves thinking there might be too much crank pressure that might cause it and nope nothing.

 

I am also tuned NA, and I have also sent my tuner data logs and he does not see any issues. I have even uploaded the stock file and it does the same thing. Just gets really annoying. With the Ecutek app I checked all of the voltages from throttle bodies, AFR and maf sensor and everything is in line.

 

Ahh..I misunderstood..I thought yours started after you went forced induction like me..
I did the same only I didn't just check I replaced everything...figured better safe them sorry with 12psi of boost.lol..
...hmm..isn't possible maybe a temp sensor? Maybe the tune is seeing Temps fluctuate?

 

It has to be a bug somewhere..I'm fi and on ethenal and your na and 93 so it can't be a tune thing..it drives me nuts too .. I give the throttle a quick hard smack and it settles back down to 750 ..does yours do the same?

 

i personally thought since our throttle bodies are warmed up by the coolant, that maybe that could be the reason why? The throttle bodies get way too hot and start altering with the intake temp and causing the car to act up.

So mine is a bit weird I will come to a stop, it will jump forward, then the idle will drop to 600rpm and then start raising to 900rpm. Also if I drive it in manual mode and down shift from 2nd to 1st it will stop normal but then the idle will start to raise. Giving it throttle while stopped does not do anything for me.

 

Could try and bypass the throttle body heater lines and see if it still does it..

 

I’m give it a try Sunday or Monday tbh. What’s the worst that can happen? Lol

 

So on my Ecutek app, I set up Bank 1 and Bank 2 for AFR and throttle position voltage. From those values, it looked like I had a leak from my test pipes gaskets. Sure enough, I was right, the passenger side had a pretty big leak. I tightened everything back up and the car idles normally now. Did a good amount of pulls to get the car heated up, and no more high idle.