You’ve surely heard of the hit song “Ain’t No Mountain High Enough” by Marvin Gaye and Tammi Terrell. The lyrics go something like “…ain’t no mountain high, ain’t no valley low, ain’t no river wide enough baby, To keep me from getting to you babe.”

That’s probably the Isuzu D-Max’s favourite tune since it practically overcame all those things to prove just why it’s the toughest, most fuel-efficient pick-up out there.

Isuzu Malaysia’s previous Dura Miles Challenge saw the D-Max drive from Bangkok to Singapore on just a tank of fuel. Obviously, this time around they had to raise the stakes to prove that its new 1.9-litre Blue Power turbodiesel RZ4E-TC engine was just as capable as the 2.5-litre mill it replaced.

So, how did they put their mettle to the test? Well, they loaded a 1.9-litre Single Cab model to its maximum permissible capacity of a ton (1,000kg) and took it through some of the highest accessible hills along the Titiwangsa Mountain Range (1,000m elevation) that traversed a distance of over 1,000km with two bars of fuel still remaining in the tank.

Naysayers are aplenty on the internet and Isuzu Malaysia was prepared to hit the keyboard warriors on the head with a keyboard of their own.

The company sent the pick-up for an inspection at Puspakom to verify its showroom-standard specifications. Once everything was verified, the journey began from its birthplace; the Isuzu-Hicom Malaysia factory in Pekan, Pahang. To keep tampering at bay, Puspakom stuck its tamper-proof seals on the weighted crates, bonnet and fuel tank cap.

For the first leg, the D-Max headed north along the East-West highway that links Jeli in Kelantan to Gerik in Perak. Part of the journey saw the pick-up ascending 1,052m before ending at Ipoh.

After a good night’s sleep, the drive continued with another climb of 1,112m up Tanah Rata in Cameron Highlands before continuing to Fraser’s Hill (1,222m) via Raub. If you thought it was all downhill from here, Genting Highlands and its elevation of 1,604m laughs in your face.

The chequered flag was finally waved at the Isuzu Service Centre in Shah Alam, Selangor with 1,145km clocked in on a single tank of diesel.

Isuzu Malaysia took the liberty of crunching the numbers for you. The on-board computer dictated the D-Max 1.9-litre returned 13.7km/litre of fuel.