Holden Colorado Engine Problems

You say it’s new, but not how many kays it’s done. I would wait until it is properly run in before doing anything rash like fitting an aftermarket chip. While they can improve the economy and performance as you say, fitting the chip would void your warranty on the engine and the drivetrain. If you are concerned about the performance first consult your dealer.

It looks like you’ve reached a stalemate. Ryco has told you there is nothing wrong with its filter and are obviously happy to leave it at that. I suggest you sit down with them and discuss your concerns face to face. If that doesn’t achieve a resolution, then take it to consumer affairs.

It's under warranty, so take it back and demand they repair it, the dealer's advice is rubbish.

You should take it back to the people who installed the gas system, as something is amiss with it.