2008 Ford Focus Diesel Dies on Hills

My '08 Ford Focus Diesel dies while accelerating on hills or under load. In third gear, around 2800 RPM the engine consistently shuts down. The engine continues to run until the fuel is exhausted (about 10 seconds). No warning lights come on and the radio, lights, etc. continue to function. Putting it in neutral and restarting the car consistently works.
We live in Norway where everybody has a boat payment and labor for an oil change runs around $50 USD (250 NOK). I’m hesitant to bring it to the mechanic until I have some idea what’s wrong with it.

Since it sounds like fuel starvation, changing the fuel filter would be a good first step.

Are frigid temperatures an issue ??

It’s cold here, but only just below freezing lately. The problem happens both when the car is cold (sitting in the garage all night) and after it’s been driven for half an hour.
Is the fuel filter easy to replace? What would a clogged fuel filter look like?

A clogged fuel filter would look just like an unclogged one, but you could not blow through it…A service manual for your car would be a big help…Diesel powered Focus cars are not sold in The States so you won’t get much help here…

Hmmm. Probably putting my lips on it is a bad idea. But a fuel filter should be pretty affordable here.

First, locate the fuel filter, sometimes they are under the car, back near the fuel tank…Then determine if you have the skills and tools needed to replace the filter…THEN go shopping for a new one…