Fuel consumption off the chart

[Fighter1]

I'm not a mechanic and even those I've talked to can't find anything wrong;
My navara D40 double cab is for some reason drinking enough diesel to start it's own AA club. When idling it goes from 6-7.5L / hour. 1st and 2nd gear is 60L / 100km. When on the motorway it's smooth at 22L / 100km. I've had some mechanics plug in a reader and check my cylinders and looking for faulty codes but nothing. Also occasionally I loose alot of power on 3rd and 4th gear. But that's not often. And it's sorted after I swap to a different gear. Any ideas? It should be about a 3rd of it's current consumption.

 

[landmannnn]

How are you heading the fuel consumption?
If it is genuinely using that much fuel, the smoke trail will be visible from space...

 

[GunMentalGrey]

Which year and which motor? How many kms on it? What’s the average consumption or how many kms to a tank?

Does sound pretty high though.

 

[BarneyB]

Are you recording each tank fill and ODO reading, & then calculating the actual consumption?

The live dash number is just a gimmick. Approximately close to actual consumption....maybe.