Jerk in 1st gear? Paranoia?
 

Wassup guys, new to this forum. Excited to say i just picked up my first z33 a couple days ago in pretty mint condition.
05 350z 6 speed. 130k

I come from 300zx and 240sx background so Nissan all the way. Anyway, car runs great OTHER than i feel some slight "hiccups" or "jerking" when going into first from a dead stop. Its around 1000-2000 rpms and going 5-10mph. Idk if its just me being paranoid but i can feel it hiccup and go back and forth. Once going over 10mph, the rest is smooth sailing. I just dont know if i should be concerned or not. Another thing to note is i notice is does this more when the car is warmed up and has been driven for atleast 20 mins. I dont want to say its just me who sucks at driving stick. Ive been driving stick for 3 years now. The other day when driving for about an hour, it hiccup pretty bad to where i thought it was a flat tire.
Any ideas or suggestions on what i should do about this? It running on 18x9 SSR's with lowering springs.
https://cimg9.ibsrv.net/gimg/my350z....309ec55fd2.jpg
https://cimg5.ibsrv.net/gimg/my350z....50e2c3aec2.jpg

Hi Brian. You purchased a nice looking car. The problems you describe could be the crankshaft sensors or the camshaft sensors. I had very similar symptoms you describe, and the fix was replacing the sensors.

WITH THIS SAID, please get the codes. This way you know what is wrong and you are not throwing $$ away by just tossing parts at a problem.

The didnt really think about the sensors because theres no CEL. There are no pending codes either. The only thing i can recall is the prev. Owner kept saying something about the flywheel and driveshaft being very loud in this car. When on the freeway, it sounds like a freaking airplane. But in regards to the jerking, no lights on dash

It's normal for the Z to buck in 1st gear when letting off the gas abruptly and re-applying, this is due to the gear ratio, OEM dual mass flywheel, and minor drivetrain slop. However if it's bucking on you while slowly & steadily applying throttle in 1st, that's *abnormal* behavior. Based on the previous owner words, it sounds like you may have an aftermarket flywheel, clutch, and possibly driveshaft? The OEM driveshaft has never been known to be noisy unless something is broken or worn out.
-Icer

Does it have an aftermarket driveshaft? Driver mod might be needed or basically practice to learn the clutch pedal. The clutch on the z can be challenging to modulate as people who try to drive my Z, such as porters at the shop or techs pulling my car in for an alignment, always have trouble and stalls the car. My clutch is stock and the car has low miles.

I cant recall correctly if prev owner said it was aftermarket clutch, flywheel or driveshaft. All i know is when going over 50, especially on the freeway, there is a very loud "whirring-like" sound as if its coming from exhaust or something. Just sounds like a jet or plane. I have definitely picked up that this clutch is different than my s13 which was super easy to drive. I feel like even we really focusing and letting off clutch steadily and light gas, it still bucks if you will. Should i be concerned?

The loud noise when traveling 50mph could be something else like a wheel bearing. I had a similar wind tunnel-like noise and I replaced the rear wheel bearings which resolved that problem.

To rule that out, raise the car with the wheels on and see if there is any play when you move the wheel back and forth.

​​​​​

or if it has aftermarket diff, and it isnt shimmed properly.....

True. Diff bushings could be shot too. OP, check to see if you've got the snail trail of dried black ooze dripping down your rear subframe.

Brian, where are you located in CA? You may want to have a second opinion on the Z. Someone with Z33 knowledge/experience should take it for a test drive since there's so many variables here. In my humble opinion, without seeing/inspecting the car, it sounds like the previous owner installed aftermarket drivetrain parts. The whirring noise, if coming from the rear could easily be the diff as Trav said or the wheel bearings as Heel said. You can also get a loud hum or whirring noise if a PU/solid transmission mount was installed or even PU/solid bushings for the rear diff.

The odd bucking issue could just be an aggressive aftermarket racing clutch or an overheated/warped flywheel and pressure plate (assuming this only happens *during* clutch engagement, if this is happening after full engagement something else could be at fault).
-Icer

Im located in SoCal, LA area or IE more specifically.
Upon paying close attention, It only bucks when the clutch is fully released. I noticed its when driving really slow like from a complete stop or even turning. I was driving really slow in 2nd gear around my school parking lot and it jerked a couple times. I know its not due to not giving enough gas. Im kinda lost tbh. Any other ideas? It can be pretty hard at times and it doesnt always do it.

Hi Brian,

If you're in the LA area, I would make a trip out to SpecialtyZ and get their take on it, those guys are friendly experts, I'm sure they wouldn't mind taking a quick test drive in your Z. As I said earlier, it's normal for the Z to jerk/buck while in low gear if your throttle control isn't smooth and steady. The Z's gas pedal is very sensitive and I sometimes struggle with this when driving on bumpy roads at low speeds. My good friend who daily's a Z32TT has also complained about how touchy the clutch and gas pedal on my Z33 is. After driving his Z32 myself, the difference is night and day. Both the clutch and gas pedal on the Z32 feel much heavier when compared to the Z33, probably because the Z32 uses a cable connected throttle body while the Z33 uses fly-by-wire. Now if the engine is stuttering on you randomly resulting in the bucking/jerking issue when in gear, then having an expert look into it is your best bet, especially if there are no codes being thrown.

One thing you should think about for improving the driving experience, is replacing the OEM clutch pedal with an RJM unit. This one mod made the biggest difference for me and improved my smiles per gallon tremendously.
Good Luck!
-Icer

Ive been driving this Z for a week now and i can definitely see what you mean by senstive gas pedal. Rev matching is still a littlr difficult, but yeah Im going to be taking a drive to Whittier this weekend. Theres a Z specialty shop there too called "Mikes Z Shop" and gunna see if they can offer a complimentary test drive lol. Im just very picky about my cars and always have something to complain about. In the end, i just want to make sure its nothing serious and i dont end up with having to replace my transmission or something. I took a quick trip to my 7 eleven around the corner and he was able to experience this "kick" im speaking of. It happens shortly after i move from a complete stop and my clutch has already been fully released.

You have to really pay attention to the vid but this is the best i can get to explaining it. Last thing i noticed is when turning and driving slow. Clutch is fully disengaged by the time it jerks. Side note, i might need an alignment as car moves with every dip on the freeway and pulls slightly to the right.

Might help if you mounted the camera on the windshield or dash. Even better would be to mount it somewhere where we can also see what the gauges are doing. Can't distinguish if its you trying to hold the cam steady or the car doing something it shouldn't. lol You could also point out the exact time it does the "bucking."

^^^^^

I second what Sparco said. I was trying really hard to watch the RPMs when the issue occurred, I think I saw it jump, but it's very difficult to tell with the camera moving around and your arms + steering wheel going in and out of the frame, also you're executing a 3-point turn requiring brake + throttle input, shifting gears, and clutching (Many variables to account for). Point out a time stamp in the video or if possible try and capture another vid while driving slowly in a parking lot or something that requires little to no steering input and no shifting, so you can focus the camera on the gauges.

If you swing by "Mike's Z shop" this coming weekend, I would also like to hear what the consensus is if they get a chance to drive the Z and reproduce the issue.
-Icer

Yeah i was thinking the same, it was a long shot with this video lol i just dont have a phone mount. But its at the beginning of the video, within the first 10 seconds. I will def try to get a better recording and if i can make it to Mike's Z Shop, ill fill you guys in. I have come to the conclusion that it only jerks when turning and after 20 mins of driving. It never does it when first driving it. Its like, kicking as i turn which is odd. Could a potential bad alignment cause this?

Wait, this only happens while you're in a turn? That's a very important observation. The previous owner may have welded the differential, or simply installed a very aggressive limited slip differential (LSD). Welding (locking) the OEM "open" diff is a common practice for those wanting to make a cheap drift car (Easy skids!). This would easily explain the jerking happening at the rear end, one tire is fighting for grip over the other while turning, this effect is exacerbated while driving at slow speeds and making tight turns. For a daily driver this is a terrible mod since it will prematurely wreck your tires and it puts a lot of stress on your rear suspension components in the process. Do you hear one of the tires chirping when this happens?

A simple test can confirm or deny this. Jack up your rear end (both rear wheels off the ground). Try rotating one wheel, the other should rotate in the opposite direction, if it doesn't you have a welded or locked diff.
-Icer

That actually never occured to me and that may very well be the problem. That sounds exactly like what you are explaining. I will def try that tomorrow or sunday! The tires do not chirp when doing this though. The tires are fairly new, probably like 85% thread. When the jerking happens, im driving very slowly.

Okay! Im so glad i was able to find the closest resemblance to my issue(s). If you skip to 1:55 in the video, that loud whining/humming sound is literally the same exact sound im hearing when on the freeway, or going atleast 50 mph and lowers/gets louder as i add more throttle. If thats the case, Im almost sure it has to be my diff which is also causing the jerking when turning? Can anyone add on to this? Just so i dont feel like im losing myself lol