Really strange one. My Xsara started to cut out at junctions and had really bad idle. Changed ICV and then it began to hedge on tick over so replaced the Throttle Pot. All seemed well and then the car started to rev to about 3000rpm when hot and under no load so changed the ICV again and made no difference. Changed the fuel filter and upon failing MOT on emissions also changed O2 sensor and MAP sensor. At the same time changed air temp sender and checked everything over. Ran OK for a couple of days and has now decided to rev to 5000rpm when hot. with all the sensors changed could the car be drawing air in after the throttle body causing it to rev. Only reason for asking is I can change standard idle by messing around near the body. Any help would be much appreciated.