Strange engine vibration 2-3K

[Andy.]

I was trying to listen for a blowing exhaust and when slowly raising the revs from 2-3,000 the engine shook enough to feel it in the whole car (Only at a standstill). Past 3,000 it carries on as standard (until 4K when the exhaust starts rattling ).

Any ideas? I can take it to Renault as it still has warantee but 1) they aren't that good at fixing the faults and 2) the garage is miles away. If I can go armed with a diagnosis it will save me some time.

Thanks all.