Hi there madge1980 and a warm welcome to Renault Forums, I'm sure one of the tech guys will give advice soon, in the mean time if you do a search you may find something useful as I seem to remember a similar cry for help,
hi sorry no the revs dont drop they start going higher if anything. i recently replaced 12 valves cos the cam belt snapped. maybe ive put it back together incorrectly as i didn't strip it! Thanks again.