Highest Possible Value of EGT?

And what about others parameters?

The EGT value is on ground testing?

Oil temperature?CHT?

If oil and CHT are normal range, EGT sensor may be malfunction.

1000C is 1832F. It's not correct. You have another issue. Maybe you instrument depending on Mfg needs a resistor in line?

Which type of sensor do you use and are they set up in your instrument correctly. I take it one gets strange readings when instrument set up and sensor type don't match.

I am using Rotax Flydat for sensor display. All other temperatures are in range like Oil Temp, CHT and Coolant Temp. EGT sensors which I am using are Rotax K-type thermocouple probes. If there is a sensor malfunction why does it show a gradual increase in temp with throttle increase, it should directly read 950 °C ot 1000 °C rather than showing a reasonable expected temp readout with throttle increase? But when I keep throttle steady at max and rpm around 5500-5700, one or two EGTs show a distrubing value of 950-1000 °C. And with the decrease in throttle and RPM, EGTs also drop to normal range.

@Roger Lee please reply in detail. I would be waiting for your expert opinion.

My instrument is Flydat and it does not need a resistor to pull-up or pull-down. It is well calibrated and shows true vales with other engine.