Initial remark is vibrating temperature oscillation seen at exhaust temperature indicator at range from 50 to 300 C during the flight.For everyone who knows this type of engine it should be steady at 450 C.The engine RPM are fixed at 43500 which is excellent.The following procedure is check the RPM indicator.Done, it is accurate.Next is to check the resistance of the wires at thermocouple system.Found to be 18,03 Ohms.Fixed at variable resistor and adjusted it at strictly 16.02 ohms.The serial numbers of thermocouple senders indicated that value. When I have approached the connector and disassemble it I have found that the pins are loose and their connection to the wires are bad. So after carefully inspection there is a one pin with signs of overheating others are too but this one is more than others.Procedure follows. Changing all four pins by new ones, Coat it carefully with thermo coater insulation , fixing the wires with clamps.Everything is now sur