Mitsubishi Triton Problems

I would be looking at the injectors first. Worn injectors are common in modern common-rail diesel engines; it could also be a sticking injector. You could also check the low and high-pressure fuel systems.

There have been other reports of rust in the Triton. When Mitsubishi was approached with a similar problem in 2015, the company offered the owner a full inspection and a Mitsubishi representative present and the promise that it would be rectified in line with the company's warranty. On that basis I would suggest you contact Mitsubishi headquarters direct and request similar action on your vehicle.

I would be looking at the fuel supply, the filters, fuel pump, and the fuel itself. If the performance generally has dropped off I would also be looking at the turbocharger.

Sorry. Clutches, like brakes and tyres, are always regarded as wear-and-tear items. It's the same for new cars. Without doubting your driving, many people are very hard on their cars.

My general rule of thumb is 160,000km but if it’s been well maintained the higher figure should be fine for something like a Triton.

The rear springs have sagged, which is common on the Triton and some other Mitsubishi models. It could well be the cause of your problem. Most owners choose to fit uprated springs to their vehicles, particularly if they're carrying loads.

You could have been on the right track with the vacuum hose because it sounds like it could be running very lean. I'd check the fuel system to make sure there are no problems with the fuel supply, and also check the oxygen sensor to make sure that's working correctly and not giving false signals.

It does appear to be a long way above the claimed combined consumption, enough to suggest it's more than a 'green' engine effect. I doubt it would drop by a third after running in. As it stands now I wouldn't think you had a case for a vehicle swap or a refund, but you certainly have a case for asking Mitsubishi to investigate and fix your car. Start by asking the dealer to investigate the cause of the problem, if it's beyond him ask him to get the help of Mitsubishi's service people. If all that fails then you could consider taking the matter further and perhaps asking for a new car. In the meantime keep very detailed records all conversations and phone calls with the dealer and Mitsubishi, and of any work done on the car. This could help later on.