hi have you had the fault codes cleared after changing the sensors? were they at fault? - go to a quality service shop does not have to be a renault dealer, just make sure they have the equipment to talk to the cars computer, dial in and fine out what the problems were/are. These cars suffer with many electrical faults - could be coil packs, de-phaser unit etc, mainly easy to fix, just need to pin point issues.
mark - megane 1.6 vvt cc, September 2010