Does anyone know what causes this? Is there a recall or TSB for it? Generally it only happens when engine braking from high RPM. It will go away if the clutch is depressed or the RPM fall low enough.

Does anyone else have this problem? It's never presented itself as a serious problem and it's been there ever since I bought the car, but it's definitely not normal. I've never had a sportscar act like the engine wants to blow up from simply engine braking. I'm going to take my Z to the dealer soon to have them look at it, and I would like to be armed with information before I go.

 

Normal.....the Z does this! When downshifting you will see a good amount of vibration through the shifter.

 

I get some rattling when I shut the car off...... but that's about it. I hate it, sounds as if the Z was an 87 ford taurus .....

 

This type of vibration does not seem normal. It is obnoxiously loud and it practically shakes the whole car. An engine brake should be as smooth as it was on the way up. It's also sporadic, it doesn't do it every time.

I've only heard from a G35 owner with the same problem. He said something about it being the fuel pressure regulator.

 

I have the same problem... although its not LOUD, I can def. feel it in the shifter at times. I took it in, but of course they couldnt replicate the problem. Ive had this problem since like... 10,000 miles

 

Bump?

 

definitely not normal....something's definitely wrong.

 

I have this issue when ever engine braking and even more while taking a right hand corner. I also have a slight hesitation in the rpms while coming down around 5K after putting the clutch in. I am very interested in the fuel pressure regulator theroy. I have been thinking it was a front driver's side motor mount. have a freshly rebuilt motor and I was hoping it would have fixed the hesitation in the rpm free fall. The extremely lound rattleing is new. I might just go ahead and install my fuel returm system with my larger injectors now to see if it clears up the problem. Any input, would be helpfull. I will try to do the fuel system swap next week and an overall inspection for rubbing parts that could be causing this.

 

i think its normal. I do a fair amount of street racing, and I get the same vibration in the shifter and/or car when I come down from high RPMs (when engine braking).

I wouldnt suggest taking it to the Nissan dealer first.

 

This sound I have is not normal. It's also not from the shifter, it's from the right side of my engine bay. It's extremely loud

 

It's probably your jake brake...

 

I thought that was only used on large vehicles or heavy equipment. That's not quite the sound either. I'll have to try to get it on video with a sound clip.

 

Sam.... it's funny you say that... because that's exactly what it sounds like. I didn't have time to respond yesterday and that was exactly what I was going to compare it to... and you beat me to it... Of course that's not what it is... but it gives the right idea...

modsz: It doesn't have anything to do with the shifter.

illbznu... I'm not sure if we have the same problem... but possibly. I havent noticed turning to make a difference... that seems like a wheel/suspension problem, although I'm not sure how that would relate to engine braking... but for me most of the time I'm downshifting that aggressively I'm going straight. I also have no hesitation in RPM. For me it is intermittent... it only decides to do it sometimes... and given the nature of the problem it's hard to replicate. It also seems like as time has gone by it doesn't do it as often or as obnoxious.

 

It sounds like from what you're describing, that the noise is extremely similar to the one I am having. Mine is just more predictable and louder it seems. Do you have a turbonetics kit or Volk wheels by any chance. It does seem like a wheel/suspension problem, but why only when in gear and decel. I will be putting my car on my friends lift next week hopefully and will let you know If I discover anything. If I can't figure it out I really don't want to take it to a dealer just to have them tell me it's probably all of my mods that are causing it. At least that's my past expereience.

 

...broken motor mount?

 

That's my best guess, but I would have thought that when the shop that just put my new motor in would have noticed a bad motor mount pretty easily.

 

I've felt something like this before. When engine braking the RPM would just fall down normally...but a few times there'd be shaking at certain RPMs. When it first happend I think it was RPMs dropping from ~5k RPM in 3rd. Other's I replicated a few times (I think it was 3rd) @ ~ 2800 RPMs. I'd go up in RPM and have it fall back, and it slightly vibrated once it hit around 2800 and went back to normal once it passed that range. It was intermittent for me as well..haven't felt it in a while.

 

My car does this about 2 -3 times in a time span of about 20 min of driving sometimes more, just as you describe the vibration and noise.

I also had this issue from when the car was new, but it has since become worse and that is why I took it to the dealer.

I took it to the dealer and was able to replicate for them. I have had my half shafts replace and now my main axel replaced. The half shafts due to looseness and the axel due to the end links being notchy and stiff.

The problem is still there, just a bit less ovious than before.


Next I think I will have them check the diff. because it only happens when decelerating.

 

I felt it a few more times today and wonder what's causing the shaking?

Another question for you guys;
When I'm in a cruising gear, say 4th @ 3000 RPMs, and I let off the gas, after ~ 0.5 sec there's a small little jerk one can feel. When I get back on the throttle normally to accelerate again, it starts to accelerate after two small jerks which one can feel.
I can't feel this in an auto type trans. Why do MTs do this?

 

My only guess is that for some reason you have slack in your drive train. It could just be something loose. But it sounds most like your backlash in between your pinion and ring gear is out and sloppy. That's my best shot at that issue, good luck!