Car juttering at ~3k RPM (again)

[Fried_Chicken]

I noticed this problem on the ZHP way back when I got it and I figured it would be the VANOS. Well I put in new VANOS seals (Beisansystems), and it alleviated the issue (~80%), but now it's back again.

Accelerating in 3rd gear especially at ~3k RPM causes a noticeable juttering throughout the car.
Any idea? I don't think the seals are going bad again. The only thing I did recently was put some fuel injector cleaner in. It may be time for an oil change.

[BADCLOWN]

Coil packs

[wertyu78]

+1. Test your coilpacks. Check for coil resistance and check codes to see where it's misfiring. Swap the coils on the misfiring cylinder and see if it moves.

[Vas]

Mileage on the car?

[Fried_Chicken]

~140k miles, I did coil packs at 100k Miles, and I'm not getting any codes for a misfire.

[BADCLOWN]

I had this issue on my 04 zhp and it never threw a code but did the same thing.

[Fried_Chicken]

I had this issue on my 04 zhp and it never threw a code but did the same thing.

Well... did you manage to fix it?

[BADCLOWN]

Yes, with new coilpacks. I had one bad one. Replaced all 6 plus spark plugs. Kept the 5 good ones as back ups

[ELCID86]

I have a similar issue. New coils helped and I'm hoping the Vanos (in the next few weeks) will also. LTCMONTANA said he had his ECU flashed and it cured his issues. Thoughts?


Thumbs, iPhone, Tapatalk.

[BADCLOWN]

ECU flash wouldn't hurt. when i bought my first 04 ZHP it hadn't had an ECU flash ever, that got rid of the 3k sputter that is common before an ECU reflash and just generally it felt a lot smoother. Because the ECU hadn't ever had a reflash it took roughly an hour to reflash it.