What feels like stuttering

[Motegi22]

When cold, my prelude doesn't seem to run very well. It seems to have a few flat spots (or what feels like) between 2k-4k.

When its fully warmed up, its much better, but you can feel it "stuttering" around 30mph in 4th/3rd gear.

It had a cam belt change 3k miles ago by previous owner, could it be anything to do with timing?

Its a 1999 2.2vtec manual and always run on v power. 100k on clock. Recent major service 500 miles ago failed to cure problem (ruling out sparks, oil, fuel filter).

[shouldbworking]

Without expensive checks ie rolling road the obvious checks would be temperature sensor, air flow meter and lambda sensors that could potentially be misreading and causing an incorrect mixture. Timing could potentially be to blame too.

[Pumaracing]

Sounds like a weak mixture. At that mileage the injectors might be getting a bit clogged. Doesn't cost much to have them ultrasonically cleaned and flow tested.