Hi,
Yeah, could be. Having a 'discussion' with Holden about covering this under warranty when it's always been complained about since new. They say it can't be a manufacturing fault because the gouge is horizontal. It's 'fair wear and tear'. Seriously! Only done 97,000km
We had the injectors replaced but it made no difference......
The fact it has a vertical gouge within a bore (or bores) isn't material in concluding anything about how the gouge actually occurred. It could have been caused by a manufacturing issue during assembly. It could have been caused by some other failure that resulted in crud being sucked into combustion chamber via the intake or exhaust. Really it could have been any number of things that the dealer/manufacturer is liable.
To claim the cause is "wear and tear" after less than 100k kms simply brings into question the lack of durability for the engine and such can be seen as an acknowledgement that the engine just isn't durable in terms of what an average consumer would expect given the vehicles price. That's a failure of ACL acceptable quality standards defined under ACL.
What is probably more relevant for the moment is that you've complained about rough idle repeatedly while the car was under factory warranty. That should be the focus of the complaint, repeated complain of poor idle. So what the dealer/manufacturer should focus on is eliminating all likely causes, one by one during the diagnostic process. As Sherlock says "when you have eliminated the impossible, whatever remains, however improbable, must be the truth"... basically new engine time if they can't isolate the cause...
It's about time the dealer/manufacturer actually pulled their finger out and did some real fault analysis to get to the root cause. Then fix the issue you've been repeatedly complaining about (since presumably new car purchase time). Whether fixed under factory warranty or fixed under your consumer statutory rights is just a back office problem not directly relevant to you. But keep in mind that repeated minor faults will raise the issue to that of a major fault classification under ACL. Such will mean you'd be within your rights to choose the remedy and thus reject the vehicle and ask for a full purchase price refund (only if you bought the car from a dealer). Such gets them a little more motivated to solve the underlying problem for you (replace the engine?).
PS: injectors were a knwn defect and they should have been replaced under warranty (either factory or statutory) at no cost to you.