Hesitation / thump /miss when accelerating from 80km/h

[tepaus]

Hello all,

Last night we took a 4 hour trip in our 2005 VZ (105,000 km) when accelerating from 80km/h back up to 100km/h, we noticed a miss and an almost a thumping when the accelerator was pushed down. When it did get back up to the 100km/h speed it seemed fine. Any ideas what we should be looking for? - i'm suspecting crook leads but just wanted to know if anyone else has experienced this.

Many thanks in advance.

[holdenvtman1123]

it is quite possibly the cranckshaft balance wheel. check the rubber around the center of the pulley

[jetboy]

it is quite possibly the cranckshaft balance wheel. check the rubber around the center of the pulley

il second tht coomon prob those harmonics

[-**wHiStLe**-]

Harmonic balancer shouldn't have worn after 5 years..
Or are they really problematic with VZ's?
Plus if it's so gone as to cause problems you would probably hear it (like a ****ed bearing).
From my experience anyway

[mattsv6]

I had a similar issue with my VZ that started around the 100,000k mark... It turned out to be the ignition coils which were not firing the spark plugs properly and causing a miss.

This only happened when using medium to heavy acceleration or trying to build up speed (say from 80-100) in 5th gear.

Hope this helps.

[andyman]

ive never heard off balancer problems on alloytecs, the crank signal does not run off the alloytec balancer either,

id be leaning towards coils, seems to be a common thing around the 100+ km's at this age, mine seems to be hesitating and getting worse in that way so ill have to do some testing sometime soon

[dave1979m]

I ham having similar probs with my 2004 model VZ. Auto Electrician is telling me its the ECU. Can you replace them with a used one from a wreckers or do you need to have them programmed for the car??

[bigdaddycool]

VZ's seem to have alot of electrical issues. dave1979m, perhaps it is the ECU, maybe it's just something shorting for a second here or there....

Try a spark plug change ....... doesn't take long. If that doesn't work, have ur coils checked by an auto electrican. Both are alot cheaper then an ECU.

[mattsv6]

I agree, could be a cheaper solution to your problem.

-Matt

[impulsive]

BDC busting out the moves mate, thanks for posting some useful info as late!

[dave1979m]

I have changed the plugs and have had the coils checked. The Auto elctrician said the next thing to check would be the computer mounted on the front of the the engine with the 2 plugs going into it. He has checked the wiring. I pulled it off and gave it to him to send and get tested but they can't test or repair these ones apparently. The car has been in the driveway for 5 days now. New from Holden these are $905. I can get a wrecked module but was wanting to know if you can just plug it in and away you go.
Thanks for the replies.