Fixed. Bad spark plug.

 

You could use a cheap wireless OBD scanner and OBDFusion or Torque Pro to create an "absolute throttle position" gauge.
On FB yesterday, Motorvate posted this:

If you try to use full throttle under 2,000 RPM, the throttle opens to 32%, and then slowly increases as engine RPM increases.
BUT, if you try to use full throttle at 2,100 RPM, the throttle open up instantly to 70%+ and increases with engine RPM.
It looks like Nissan is preventing a high engine load at low RPM.

Just a suggestion

 

That's awesome!!!
Would love to see some videos to compare.

When you went with ebay coils and plugs I take these plugs were the culprits and didnt last too long?

From what I've been able to gather many times Ebay/Amazon plugs are fake 70% + of the time.

 

The red line was the beginning stages of this tune, the green line is were we got it to after a lot of work and blue is a normal G37. As you can see you can not tune this issue out of a G37. I have some things to add to this thread and I will be composing my thoughts and leaving them here. Another issue I was incurring was a clutch sensor not functioning right which you can see on the Laptop screen, my tuner was depressing it and it didn't register at all and I will need to figure this one out as its a crucial part to switching and engaging maps on a tune. I have already replaced the ACSD Clutch Switch and the clutch Interlock Switch and brought the car back to still have it read the same which means it's more then likely the BCM. If that's the case the BCM could also be causing the RPM issue as shown in my DYNO pics. If you have a sunroof leak or windshield cowling put back lapped wrong both these can run water into the boot that protects the wires going through the fire wall into the BCM. My boot also happens to have a crack on it and my cowling was not lapped right. I love a good rabbit hole and I refuse to lose this one. To get everyone up to speed I just purchased this car, I was an owner of a 2013 370z Nismo (car totaled) and this is my next project. I have upgraded rear diff brace, did Z1 intakes, Berk test pipes and Z1 catback exhaust as well as sparkplugs and oil change. Upon test driving before purchasing I noticed the lag in power and thought it needed to be woke up, well I woke it up with Mods and this situation in the RPM range even after tune is still present and hindering performance.

 

Any updates? I'm curious if you've found anything. I drive around the isssue now but every now and again it gets me🙃

 

I cant believe there hasn't been a fix for this yet.. mines in the same boat. Hesitation at 2-3k. Fine when cold. I'm going to try throttle bodies next. I just filled the intake manifold bolt hole in the center that holds the cover on. Heard that can crack and cause a vacuum leak. It's kind of what this feels like. Maybe the crank sensor too.

 

Well i fixed my hesitation. Checked the brake switch.. ecutek read a bcm code B2555. Brake switch... so i replaced it. Hesitation was gone till the code came back from the ecu memory. It cycled and then finally disappeared after driving a bit. (My regular code reader never saw the code)
But the hesitation came back. My cars neutral switch was ripped off at some point (previous owner changed the motor and messed up those switches) and a new sensor and plug needed to be installed. Now I figured I had to clean throttle bodies or something else to get this to go away... but because I was throwing the p0850 code (neutral switch). the hesitation remained... but once I hooked up the new switch.. the hesitation is completely gone. Clean smooth acceleration straight to redline. It feels great now!! Oh also it idles properly. Exhaust sounds better! Doesn't idle high, drops to idle if I'm at speed and push the clutch in. Before when I pushed the clutch in the idle would be high until I came to a complete stop.

so maybe this hesitation is some sort of minor limp mode? Any type of small code puts it in that mode? Very bizarre thing. Glad i figured it out so fast! Its great when working right!!

 

Part Number? I reckon it wouldn't hurt for me to try it🤷🏾‍♂️

 

which part? The brake switch? Its 25320-JN00A. Just unclipped and twist. Took me 1 minute.
took some driving for the code to go away. Has to run its cycle to clear the code. But i'd check with a GOOD reader for any bcm codes. As my regular reader wouldn't see them.

 

Ok so further evidence toward any bcm code... c1705 code today.. low right tire pressure. Hesitation was back... or more like minor hesitation.. it stumbled a little bit but was still pretty smooth... Filled the tire back up and cleared the code... hesitation is gone.. (of course lol) I'll edit this post after I'm sure the code isn't coming back and the hesitation stays gone. (Barring another code &#128518

 

Thought I would add some observations if anyone is still following

I noticed the g37 limits the RPMs to about 4k while in Neutral+ not moving...so I was wondering if there is a transition from what the engine will limit coming from stationary to moving as the computer adjusts for the speed or a gear selected, because I notice this when I slow down and creep up my driveway, which is kinda a stop so i dont bottom out, then put in first out of a quick neutral. From there has I give it gas it's like there is no gas pedal even pressed for 2 seconds

When engine is colder, the idle RPMS are slightly high around 1k and I notice the hesitation is not there. I usually end up releasing the clutch hard because the throttle is more crisp then it would be after the high idle is gone ( engine warm, what I am used to when driving over time). If I could set it so the engine always has a high idle I feel it would run great

And that leads me to the last observation because someone mentioned earlier about the mufflers restricting flow. I notice when the engine is warming up, only a few minutes into driving out of my neighbor hood, I roll through a stop sign and hit the gas hard, there is no hesitation (every day I drive that way). At the same time I hear some different noise not really sure how to describe it but it sounds like something is jiggling in my mufflers. I only hear that noise when the engine is colder...If I get on it a second time even a few minutes later is does not make the same sound.

Let me know what u guys think