Engine performance

Welcome to the forum.

Sounds like some kind of sensor error. Have you had any warning lights at all.

If not you need to get it connected up to check for error codes. Either take it to a garage or try yourself by buying a code reader. You can either get something called opcom. Or if you have an Andriod phone or tablet you can pickup an OBD2 reader. Their are a few other ways but they are the most common.

Saying that if you don't get a warning light you might not get a code.

If you get a code at least it gives you somewhere to start looking for the problem.

Is this pause related to when the transmission is changing gear?

I seem to remember reading a while back that a pause when changing gear was a symptom of potentially more serious problems with the box.

I don't remember all the details, but low transmission fluid, the torque converter and clutches were mentioned as possible causes of the brief pauses.

I'm not saying that is what your problem, but I would definitely say you should always get transmission problems check at the earliest opportunity. If they go baddly wrong, you might have to spend a fortune getting it fixed.

Sounds like a high pressure fuel pump fault very common
On higher mileage veichles

I have a 12 plate 2.2 diesel manual with a similar niggle which is more noticible when towing our caravan. Certain times it is gutless then there are times when it tow's like a train ??I've been told it may be a sticky "Egr" valve, going for service soon will be having a word withservice dept !!