engine surge @ 2800rpm

[percypassat]

Went to overtake tractor yesterday and as i accelerated quickly in third gear, engine seemed to miss and power dropped off. Thought nothing of it but over the rest of the journey it happened a couple more times. I realised that this was happening at 2800rpm if acceleration was anything other than slow. This happened in any gear if acceleratin was fast. If acceleration remained slow i could go above 2800 rpm(80mph). Fuel economy seemed to be down a little too.

Any ideas?