Mitsubishi Triton Diesel Problems

You'll find most diesels no matter the brand require regular valve clearance adjustments. To avoid surprises like this I always urge people to do their homework on the cost of ownership before they sign up for their new car.

It’s a great feeling when having spent many tens of thousands of dollars you get treated badly by the dealer isn’t it. Thankfully it’s not the norm, but it does happen and it shouldn’t. If I were you I would be very angry that I have been sold a car that is faulty and I would demand a replacement car, or my money back if they couldn’t fix it within a reasonable time. A week or two should be enough to come up with a fix; a year or more is ludicrous. You need to stand up for your rights.

I’m surprised the dealer didn’t try and sell you a more powerful sound system! You could also check the firewall and make sure there are no gaps or openings that are letting the noise through. If there are seal them. Having made sure all is well there you could get some sound deadening material and apply under the floor covering on the firewall, floor and transmission tunnel.

The injectors used in all of these Japanese common-rail diesels wear and that's likely to be your problem. The only course of action is to replace them, as you have been advised.

You don't say if the engine is a petrol or diesel, but I'm guessing it's a diesel. If that's the case it's likely to be excessive fuel, which could be an injector problem, or a fuel pump issue. Get it to a diesel mechanic, who should be able to sort it out.