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I have a 2007 VE Commodore Omega Reg ECB990 that has developed a misfire. The codes say its a random misfire on cylinders 2,4,6 . I have replaced the 6 spark plugs and the coils for the faulty cylinders. Checked earth connection, coil connections etc. Still no improvement.
Your help would be appreciated.
Thanks Peter

You replied
It looks like the misfire is all on the same engine bank, so the things left would be looking at the signal output from the ECU which tells the coils to fire. It may need a bit of electrical system diagnosing. I can also see connection issues with the fuel injector wiring harness and multi-plug, have been known to create a misfire.

I have been to auto-electrician and he thinks it is a stretched timing chain. I know this is common problem for VE Commodores, Can you please give me a rough estimate of what the costs might be?

Hi there,
Now this type of fault is usually expensive and I would say the cost would be in the thousands.
However, for a more accurate figure, I recommend calling a repairer who can obtain parts and labour costs to do the job.
http://locations.aa.co.nz/search/auto-centre