I have a 2002 Clio, also blue if that makes a difference. We have just paid #420 to have the
casing repaired for the same problem you mentioned of losing power without warning and only being able to do about 20-30 miles an hour till you stop and turn the car on again. We still have that problem and now the garage are tellling us it is 2 faults. We now need a new wiring loom which will cost about #450. Not sure where we stand on being told it was one thing and paying out and now being faced with another similar bill to fix the original problem. The garage are adamant that there was 2 faults not one.
Anyone got any advice. It seems as if this is a manufacturing problem and as it is potentially very dangerous, should renault not recall the clio and do this work free of charge??