Intermittent loss of power

You don't say what size engine ? whether petrol or diesel ? Common fault on some models are coil packs which can cause this fault .

apologies - 1900cc Diesel , Could it be the fuel injectors?

No problem . May well be injector/s . Could also check / clean EGR valve and check all vacuum pipes . If still having probs may need to get a diagnostic scan , sometimes cheaper in the long run , rather than guessing .

A common problem is the air dozer sticks due to carbon build up.This causes lack of intake air .It seems to be noticable at about 2000 rpm.if you take off the pipe at the front you can use a mityvac to operate the butterfly and see if it returns correctly. You will also see the build up of crud in the housing.

On my 1.9 D when the engine lost power and when coming to a stop the engine rattled like mad, then you stalled when trying to start off , it was the advance solenoid, part cost about £75, 10 years ago, easy to fit [just like a spark plug] still got the Y reg berlingo from new and running well with only 70k on the clock