Hi there,

Just got myself a mint used g35 and I'm pretty excited. ^_^
The only problem I've encountered is this "flat spot" in the rpm range.

The flat spot is at 2000 rpm and lasts for +/- 100 rpm. Mostly noticeable in first gear when accelerating from a stop. The rpms climb steadily and slow briefly at 2k before continuing perfectly. The issue may be present in second gear but it's much harder to feel.

I tried injector cleaner, cleaning the MAF and throttle body to no avail. I've done tons of research and can't find a similar issue with other g35s or any other car really. I'm really stumped.. Anyone have any ideas??

Attached is a video of the problem occurring, my foot is gradually applying rpms in neutral as if I was accelerating from a stop. The pause in the rpm range doesn't last that long when actually driving. (Problem is much easier to see when reving in neutral)

Thanks for the help!


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Under hard accel (WOT)? And is your vdc off?

Edit: oh, nvm, I just read that it does it in neutral. That's kinda weird. I definitely don't have that.

 

Yea it does it with the vdc on and off.
The flat spot is there when accelerating slowly aswell as WOT.. But more noticeable at slow speeds.
I have no idea what it could be, I've asked a couple mechanics to drive my car and they've never felt that flat spot before.

 

http://forums.nicoclub.com/got-my-ca...s-t476034.html

Look at the post from Feb 3 2010 at 10:35am. It describes some opening of a power valve (although this is about an m45) at 5krpm. It sounds like what you're talking about, and if all Infinitis have that, maybe yours is malfunctioning at the wrong rpm..?

 

Thanks for that link, I'll have to read up some more on it.
I found another thread which shows similar issues but it's related with a valve in the evap canister.
I'll try that the evap valve after work and hopefully that's the problem haha

 

Did you ever figure this out? I realized I have this same thing at 4500rpm and only under light to med throttle. WOT it doesn't happen (or is extremely unnoticeable anyhow). Doesn't seem like anything harmful, but I sure would like it if it weren't there. Was it the evap canister?

Just like your prob, its just like an anemic feeling for about 100rpm (starting around 4500), then goes away. Kinda weird. Never noticed it til I recently tuned my car and I was messing around when I was data logging at different throttle positions thru the rpm range.

 

Scragglerock hmu

 

Actually I just watched your vid and my rpms don't actually pause like that. Its more just a feeling. Hmm..

 

The flat spot is more of a feeling while driving. That video exaggerates the severity of the flat spot. It's a very brief spot exactly as you describe.

I still have not figured out my issue unfortunately and I'll probably end up paying a pro for diagnosis.