<![CDATA[MY350Z.COM - Nissan 350Z and 370Z Forum Discussion - Engine & Drivetrain]]> https://my350z.com/forum/ VQ Power and Delivery en Wed, 20 May 2026 20:58:54 GMT vBulletin 60 https://my350z.com/forum/blueevolution/misc/rss.jpg <![CDATA[MY350Z.COM - Nissan 350Z and 370Z Forum Discussion - Engine & Drivetrain]]> https://my350z.com/forum/ Groaning noise??? https://my350z.com/forum/engine-and-drivetrain/629715-groaning-noise-new-post.html Wed, 20 May 2026 16:07:43 GMT For the past few days Ive been hearing this sound and I have ZERO clue what it could possibly be. I DO know that... The noise ONLY happens after I drive the car for a little bit and shut the car... For the past few days Ive been hearing this sound and I have ZERO clue what it could possibly be. I DO know that...

The noise ONLY happens after I drive the car for a little bit and shut the car off.

If anyone has any clue what this could be, please Imk. Any and all help is deeply appreciated!
Attached Files
]]> lystroi https://my350z.com/forum/engine-and-drivetrain/629715-groaning-noise.html intake manifold fitment issue https://my350z.com/forum/engine-and-drivetrain/629714-intake-manifold-fitment-issue-new-post.html Wed, 20 May 2026 13:09:18 GMT Im running into an issue putting my engine back together after a rebuild. I have the aluminum valve covers from CZP and the kinetix velocity intake manifold. when taking everything apart I found... Im running into an issue putting my engine back together after a rebuild. I have the aluminum valve covers from CZP and the kinetix velocity intake manifold.
when taking everything apart I found the plastic PCV nipple on the right side valve cover that connects the hose to the left valve cover was broken. no big deal. its plastic after all. thought it got broken handling it.
fast forward to now going back together I replaced it with upgraded aluminum fittings also from CZP. the intake manifold chamber hits on that right side fitting before it can seal to the lower runners. like it needs a good 5mm of spacer put in.
my issue is I cant find an orientation to make it work, thinking I could swap fittings around or clock them. compared to the factory fittings they appear to stick out of the valve cover the same amount and orientation.
if anybody can suggest a solution or point me in the direction of a spacer that might exist out there somewhere that ive been unable to find.
also if you do have a kinetix velocity manifold, here is a reminder to double check the fit between the RH valve cover cross over fitting to make sure it is not busted open. ]]> Bolognahammer https://my350z.com/forum/engine-and-drivetrain/629714-intake-manifold-fitment-issue.html <![CDATA[Title: VQ35DE Misfire Under 4k RPM – No Codes, New Coils & Plugs]]> https://my350z.com/forum/engine-and-drivetrain/629713-title-vq35de-misfire-under-4k-rpm-o-no-codes-new-coils-and-plugs-new-post.html Tue, 19 May 2026 11:19:02 GMT Hey guys, I’m chasing a weird issue on my rebuilt VQ35DE. Problem: I’m getting a misfire/hesitation under ~4,000 RPM, mainly under light to moderate load. Once it gets past that range, it... Hey guys,

I’m chasing a weird issue on my rebuilt VQ35DE.

Problem:

I’m getting a misfire/hesitation under ~4,000 RPM, mainly under light to moderate load.
Once it gets past that range, it runs completely smooth and pulls fine.

After 15-20 mins for so it goes away completely.


Details:
  • No fault codes (CEL not coming on)
  • New coils
  • New spark plugs
  • Issue only happens under 4k RPM, then disappears
  • Engine is rebuilt and has only 62ks on it
  • Break-in oil was used and has been running for a short period
What it feels like:
  • Slight bucking/jerking under load in low-mid RPM
  • Clears up completely once past ~4k RPM
  • No issues when just revving in neutral unless I try hold the rpm at 2k or so (noticed it when bleeding the system)
What I’ve considered so far:
  • MAF sensor reading incorrectly / dirty MAF
  • Possible vacuum leak
  • VVT / cam timing issue (oil pressure related?)
  • ECU not throwing codes even though trims may be off
What I’m asking:

Has anyone seen similar symptoms on a VQ35DE or similar setup?
What should I check first—fuel pressure, MAF, vacuum leak, or VVT?

Any direction would help, trying to avoid throwing parts at it.
]]> z33alexander https://my350z.com/forum/engine-and-drivetrain/629713-title-vq35de-misfire-under-4k-rpm-o-no-codes-new-coils-and-plugs.html I did a bad, bad thing... https://my350z.com/forum/engine-and-drivetrain/629709-i-did-a-bad-bad-thing-new-post.html Tue, 12 May 2026 23:40:13 GMT I had to replace the alternator belt yesterday. I accidentally lifted the car alittle bit by the oil pan accidentally. I thought I had the jack deep enough to reach the circular parts of the... I had to replace the alternator belt yesterday. I accidentally lifted the car alittle bit by the oil pan accidentally. I thought I had the jack deep enough to reach the circular parts of the subfrrame K brace, but of course not.
I corrected the issue quickly, but now my car sounds like it has a new rumbly exhaust, and the engine is tilted upwards.

I didn't notice the engine tilt until after I test drove the car, and it's overheating. The hood is rubbing the plenum now.

I think I bent the oil pan to where the pickup tube is starving for oil.

It's raining now, so I can't jack the car up and inspect it.

Feel free to take shots at me, but I'm looking for what to look for, motor mounts destroyed, etc. ]]> tommyhawk13 https://my350z.com/forum/engine-and-drivetrain/629709-i-did-a-bad-bad-thing.html P2101 https://my350z.com/forum/engine-and-drivetrain/629708-p2101-new-post.html Mon, 11 May 2026 17:55:50 GMT Hello, I just changed the valve cover gaskets and spark plugs on my wife's Z. It is a 2006 enthusiast 6sp with 99k miles bone stock. After doing the job, I am getting the p2101 code. I did the gas pedal reset but the code comes back as soon as I start the car. I am going to check all the connectors again. If I don't find anything loose or damaged, I guess my next step will be to clean the throttle body. And ideas of something I may have missed? I am a capable mechanic, just not a nissan tech. Also, while I had the plenum off, my grandson moved the throttle butterfly open and closed. I know that can damage the throttle body actuator, but one time? Thanks for looking. ]]> jet tech 69 https://my350z.com/forum/engine-and-drivetrain/629708-p2101.html Time for a new timing chain?? https://my350z.com/forum/engine-and-drivetrain/629687-time-for-a-new-timing-chain-new-post.html Sat, 25 Apr 2026 07:48:02 GMT Hey guys. I come seeking guidance. Long story short, my 2004 350z has been giving me some grief. It all started when my CPS (crank pos sensor) died on me last year. I replaced the visually... Hey guys.

I come seeking guidance. Long story short, my 2004 350z has been giving me some grief.

It all started when my CPS (crank pos sensor) died on me last year. I replaced the visually broken sensor with an aftermarket sensor and happily continued on. A month or 2 after then I experienced the same symptoms and assumed a dud CPS. Replaced it again, but that didn’t solve my problem.

I then suspected cam pos sensor. I took the car to a workshop to put in a new clutch and smf and asked them to fix the issues while they were there. They said that they ran some diagnostics and that my timing chain is stretched (I wouldn’t be surprised if that is the case as the car has 210k km on the clock). That job is too big for them and told me to seek help elsewhere (they gave recommendations). I can do that job myself, but don’t want to unless I have to.

AI then went and sought out a second opinion from a guy that specialises in Z’s but is on the other side of the country. He reckons its just non-OEM sensors causing all this nonsense. I replaced the CPS with an OEM sensor - car still sad. I’ve now ordered OEM cam sensors - they’re arriving next week.

In the meantime, I dug up my old 2-channel oscilloscope and ran some tests.

My symptoms are as follows: All sensors installed - car won’t start. Unplug CPS - car starts and will allow me to drive around a bit, but it will ultimately die on me.

When I ran the scopes, I got some interesting results. Some of the signals seem to be inverted, which is super weird - hopefully the new OEM sensors will fix that. (For info - the aftermarket sensors were Bremi’s). I also noticed that the timing was a bit out (I think).

My scopes were taking during crank as the car didn’t want to starts. Are there any experts here that can tell me if the chain is stretched or if I’ve jumped some teeth? I have also attached a scope that I found online of a healthy vq35de at idle.

Thanks,
Rob



Both cam sensors
Both cam sensors

Healthy VQ35DE
Healthy VQ35DE
]]> Rob189 https://my350z.com/forum/engine-and-drivetrain/629687-time-for-a-new-timing-chain.html