98 Suzuki swift problem..

Hey how are you going I don't know if you will be able to help me but. Have just brought a 98 Suzuki swift 1.3 litre an the petrol temp an rpm gauge doesn't work when you get to about 40kph. The rpm gauge drops out completely the temp gauge goes right up an the fuel gauge goes right up but then when I come to a stop an let the car idle rpm gauge kicks back in temp an fuel gauge go back to normal also . Any ideas ??