Should I be using fourth or fifth as my main gear when driving long runs?
Fifth gear uses probably four or five horsepower just to run the gear. If you were towing a trailer, ran into a headwind or were on a constant uphill, you’d be far better off, fuel economy wise, to use less throttle in a lower gear like fourth. Fifth gear isn’t as robust as fourth either and will wear out quicker. Fourth gear, in a gearbox, is generally straight through and not using any gears at all, where fifth is using just about everything.
Maintaining and servicing your 4WD can be a costly process. If you go off-road a lot, you’re probably more than aware of some of the issues that can arise – poor quality or badly fitted parts can break and cause more damage, heavy towing or rough conditions can accelerate wear, and the expense involved in making sure your rig is running smoothly can skyrocket. But there are a few bits and pieces that can be carried out at home to make sure your problems (and costs) are kept to a minimum......Read More
One of the most common reasons for excessive fuel use is carbon build up in the engine, particularly in the intake system.
Are there any other ways to stop that from happened or fix it?
Carbon build up gives the wrong signal to the ECU and tends to upset air fuel mixture readings. Apart from cleaning it out, which is expensive but of course only the ultimate way to fix it, I personally like to use the vehicle harder for longer runs (at least two 1 hour runs a week). I think you should use a common rail diesel fuel conditioner of some sort to keep the injectors clean and you don't get the carbon build up.