I am having a small issue with my 04 sedan automatic. When I accelerate hard I get a small bog/hesitation at ~3500rpm, most noticeable in 2nd and 3rd gear accelerating. Its even more apparent when I drive it in manual mode. After it passes that 3500-3600 rpm point it pulls very strong. Its like the car loses fuel/spark for a brief moment and then continues to pull. To my understanding this is at/near the VTC engagement??

Car has 160k miles. No mods (yet). Fresh iridium NGK spark plugs last week. I changed the oil about 600 miles ago with LM 5W-40 synthetic. Oil level is perfect, I check it once a week (because VQ). No check engine lights.
This is my second G35, I had an 05 with over 250k miles on it that I sold last month. It didn't do this, it was very smooth transitioning into the higher RPM range.

Has anyone else experienced this? Is it normal on 03/04 vs 05+? I read on another forum that there is maybe a software update?
I searched and it seemed like most the other posts/problems were related to a limp mode type situation where the car stops revving at a certain rpm. Mine is more like a stumble it seems.

 

Have you pulled the plugs to inspect them, might have one that is showing you what the problem might be.

Also check all 3 vacuum lines and the intake duct for cracks or any loose hoses.

Clean the MAF.

Do all the resets.

https://www.nicoclub.com/archives/g3...procedure.html

Also get the vehicle on an OBD2 scanner, preferably one that can log data and watch your O2 sensors, ignition timing, and cam timing to see if something goes bonkers. Also check for any hidden codes, might be the start of a cam sensor failing and it's only intermittently failing so it's generated a hidden code but not bad enough to trigger the SES light.

 

I’m having the same problem, I changed the spark plugs and brakes then cranked the car up, it automatically sounded louder then usual and ran with very little acceleration and idled horrible. So I went and checked the fuel injector, replaced the coil packs, gasket,I saw there was a little oil in the spark plug tube but I don’t think it was enough to affect it. Although after I replaced the gasket it ran a little better but you can still feel it like it’s not getting enough power. I think it’s the cats 🐈, any pointers????!!???

 

Drive to Nissan for a diagnostic, it's cheaper than randomly throwing parts at the car hoping something will fix.

 

Which gasket did you replace??

Mine still has a small hesitation, but it is practically non existent when going WOT from a stop or downshifting/kickdown a gear or two.
My car seams to run fine otherwise.