srsairbags

Hey Guys . . need some expertise here

Im a new 07 Z enthusiast (HR) owner (in FL). My z has 30k miles on it and its been 3 weeks that i got it. Since getting it, i have noticed that when the car is cold, it jerks at low RPMs in any gear . i know this sounds funny and you may think that im in the wrong gear/rev range, but I am used to MTs (just not a z). I am just wondering if thats just me or is it something with the throttle position sensor or the o2 sensor . . . etc etc thats wrong.

Also after getting the car i had the diff and MT fluids changed (redline fluids as mentioned in the DIY) . . . jerking before/after remained the same.

I always warm up the engine for 2 mins before driving until oil pressure drops to 45 ish . . i live in an appartment community and have to drive the first quarter mile at slow speeds 15 mph . . this is where i see the car jerk a lot in 1st and second gears . . after i join the main road and drive for a mile or so, the jerking dissapears . . now even at low rpms, the car/engine runs smooth . . . .

Do i need to do a throttle position sensor reset, or an ECU reset etc . . ? ? or is it just me and i suck in driving ? ?

Thanks a lot guys

srsairbags

oohh shoot . . wrong place to post this . . my bad. . how do i move to repair / maintenance . . ? ? ?

Count Driftula

iTrader: (1)

just to get a clearer idea,

if you are in 1st, clutch out, rolling slowly at low rpms and depress the throttle smoothly the car will jerk over and over through the rpm range?

srsairbags

yep, with clutch out teh car jerks upto 2k range when cold . . . but once its hot it wont even jerk at 0.7k (clutch out) . . .

ALMcCoy

I have experienced this type of issue also and mine was accompanied with the SLP flashing light on although the road surface was dry.

Dr. Venture

iTrader: (19)

My guess would be that the CEL would be on if it were the TPS. Although i did have a customer whose Z had a weird RPM jolt at low RPM's. It was an AUTO though. But After going the all the usual BS to figure what was wrong and we even changed the Throttle body. All it required was a damn Throttle body reprogramming that took 10 tries. Perhaps that is your issue.

srsairbags

@almccoy thats strange . . i have no CEL or SLIP light come on . . . at any time . .

@ Dr. Venture . . i have been thinking to get both teh throttle bodies cleaned . . . but am scared as its not mentioned in the maintenance schedule . . . . does the throttle body reprogram involve taking off the intake ?

DavesZ#3

iTrader: (26)

Any mods done to the car? Is it possible previous owner had some engine mods or in like CAI, Popcharger, plenum spacer?

Dr. Venture

iTrader: (19)

Hmm...only in second gear on a blue moon when ia m making a left onto a major highway from a side street would my Z jerk. But that is cause i allow it to go to a low low low rpm in the process. I honestly just think, despite your Manual Skills that your in a low rpm going through your development.

srsairbags

as far as i know . . its completely stock . . i changed the air filter elements with NAPA WIX filters cause the old ones were kinda dirty . . . . which makes me wonder if the throttle body may be dirty too . . . (pessimist ) . . . . i dont think there is a plenum spacer for the HR . . . but im a noob soo . . . . .

srsairbags

i sure hope that is the case . . . . but a little voice inside my head says . . clean TB, reset TPS, change plugs, check battery, replace o2s . . . blah blah blah . . .

Dr. Venture

iTrader: (19)

on rare occasions would one of those things be a problem with out causing the CEL to come on. So rare that only DUKE's Z has had this issue thus far to my knowledge. (for me at least)

For ***** and giggles why don't you check to see if there is a pending code in the ECU regardless of having the CEL on?

srsairbags

makes seance . . ill stop by autozone tomm and check the codes . . . . and update tomm . . . thanks

davidv

iTrader: (2)

Its July. How the hell can it be cold in Florida!

blue350zed

iTrader: (14)

It's not cold at all...I promise.

srsairbags

just did a code read at the neighborhood autozone . . and no codes came out (which is good )

i agree its definitely not cold here . . . more like 85 . . .

i meant cold as in ambient temperature is coldER than operating temperature . . .

bmccann101

iTrader: (16)

i am ashamed for opening and reading a thread on manual jerking. bah ha ha...

mistanismo

iTrader: (1)

^ This.

donkinuts

iTrader: (3)

Yes, I noticed this too on my '08 as well. It is more like mild jerks that occurs between gear shifts. It happens in low rpm (1500-2000 rpm) which goes away soon enough after the engine is fully warmed up.

srsairbags

exactly . . . wondering if this is an HR only issue