Misfire at idle

[Chris_90]

So with the zx build still hanging in the balance I thought I'd have a look at few of the issues. It has a "misfire" at idle assuming thar what it is, it causes no issues when driving just does it at idle and when it misses throws a tiny amount of smoke out. It does this weather it's hot or cold after 70mile drive it still did it. I was thinking possible injectors because as far as I know there the orginal ones and nearly on 182k would that be something worth trying? 

Here's a video

https://youtu.be/KetzgmQOd98

So what do you guys think the issue could be hoping it's something simple and not problems with the engine.