Isuzu NNR Pricing and Specs

Sandy conditions are incredibly hard on every aspect of a four-wheel-drive. The sand itself constantly shifts under the tyres and clings to them as well, dragging them down and making the engine and transmission work very hard to maintain progress. You may have already noticed that you use a lot more fuel in sandy country and it’s all because you need to be constantly making more power to maintain speed than in normal conditions. Turbocharged engines and automatic transmissions, in particular, can get very hot very quickly in sand.

With that in mind, it’s very possible that something in the driveline got hot enough for the car’s computer to go into limp home mode to protect what ever was hot from damage. Limp home mode often involves limiting engine revs and turbo boost, both of which contribute to heat production. This would explain why the car would not climb a crest but came good after a break.

It's true that new engines can be 'tight' and this can lead to higher fuel consumption than they achieve with a few more miles on board. And since you're almost at the 30,000km mark now, why not try the dealer's advice and see if things start to improve.

The MU-X was never the most fuel efficient vehicle in its class, but even so, 12.2 litres per 100km on the highway sounds a little excessive (although not as much as you might think). I'd expect this vehicle to return highway fuel economy figures closer to 10 litres per 100km or maybe a bit less.

However, there are several factors that might be skewing your results. The bluff aerodynamics of a vehicle like the MU-X mean that even a slight headwind can increase consumption. So can the addition of accessories such as a bull-bar and roof racks. A set of roof racks on their own can add a litre of fuel to every 100km travelled, and that's if they're not loaded. Throw a spare tyre and some gear up there and it's even worse.

Bigger (taller) tyres can also increase fuel consumption, and so can running your tyres at too low a pressure.

This needs to be sorted out quickly as a car that you can't be sure is in Park is always a potential to roll away on its own causing who knows what grief and damage. It sounds like there's something amiss with the way the gear selector is talking to the actual transmission, and any resistance in the action of the shifter really shouldn't be there. That said, you do need to have your foot on the brake to select a gear from Park, so maybe you're taking your foot off the brake pedal prematurely.

You're possibly correct that the two issues are related as a car that thinks it's not in Park, will probably not want to allow you to use the walk-away locking mode. But here's the good news: This is absolutely a warranty issue and Isuzu needs to fix it at its cost.

Book the car in to be inspected as soon as possible and, in the meantime, make sure it's parked somewhere from which it can't roll away. Physically chocking a wheel (with a house-brick, a rock or whatever) isn't a bad idea till it's fixed, either.