Dodgy coil pack?

Hi, I am getting a misfire when starting from cold. Seems to be getting more regular. If I hold the accelerator to keep around 2k revs, it will eventually settle after 10 - 20 seconds? Car normally drives fine when you are running about, just on start up. I know sensors pack up, but heat is normally when these show up. Is a coil pack on the way out?
Cheers

Yes it's possible, lots of fuel about at startup to kill a weak spark. Can you identify which cylinder has issues, possibly the state of the plugs just after starting, wet or fouled could be the cylinder. You could then move the packs around see if it follows the pack or stays with the cylinder.
Not using coolant are you?
I had a cylinder miss fire at start up (not a Jimny) and it was coolant in the cylinder. First 45 seconds it misfired until it had cleared the water and warmed up. The sparkplug (and piston top) for this cylinder appeared spotless compared to the others, literally steam cleaned.
 

A failing coil pack will often show a misfire under hard acceleration and also higher revs.

Apart from what Scimike says (my first thoughts) I would add water in the fuel tank or a weak battery. A dirty throttle body or even a sticky injector can all give a misfire.

I suggest start with the easy things first and work your way through the list.

If you take the coil packs out inspect them for small cracks. You can also measure the resistance, compare the readings of all coil packs and the one which is different will be the faulty one.

Robin

Thanks both. No water loss (and no white smoke from exhaust). Battery was new a few weeks ago. Haven't checked the plugs yet, and hoping no water in the fuel tank - not done any deep crossings for a while, and recently filled up.
Cheers

Wynns Dry Fuel will clear water from the fuel tank - it's a type of alcohol (isopropanol, probably) that enables water to mix with the petrol and be burned.  You might need more than one treatment if there is a lot of water.

The extra ethanol in E10 fuel should do the same.