Will changing the plugs fix this problem.

are you sure its not failing? Did you try to take out the plug with the spark plug in it and put it on somewhere on top or metal surface and try to fire up the engine? It can possibly be your spark plug wire needs to be replaced. If you need to replace the wire then l would do this. Put all the new ones on the ground. Disconnect and connect 1 by 1 that way you do not mess up.

change leads too, infact, change leads around first, and see if the problem moves with it.

check what is the problem

Hi first up you need to see if the plug is faulty or a lead, Change the plug see if there is any oil on it, If so you have a piston or head problem if not a simple plug and lead change should do it.if the problem still is there check the distributer cap for cracks or faulty rotor button. Good luck.

If the car is a megane or scenic,They have a seperate ignition coil for each cylinder,These fail often,And is the first thing to replace.
They cost around £35 from the autofactors.

It does sound like one of the ignition coils has failed, the ones fitted to the car have now been superseded by a modified coil, part number 8200405098, they are £35 + vat from a dealer.

But if the car is under four years old then take it to a dealer as there maybe a goodwill contribution from renault.