The ecu on my supersport has been doing odd things again with the idle this weekend. PW at idle is usually around 99. On startup many times but not always it goes up to 104 or 105, which is about 55,000 rpm, stabilises there, and then pushes the pw and the revs higher, up to 106 or 107 / 56,000 rpm, stays there for a while and then very very slowly brings it back down to 99/45,000rpm. Then at the end of the flight all the way down final approach and taxiing back in the engine is idling far too fast, I attach the data terminal and it is reading 105/55,000 rpm. On some other flights the idle is correct at the start and correct at landing. I tried the 5 seconds throttle up and 5 seconds throttle down but that did not solve it.

Why, once it has started and is idling too high already, does the ecu wait a while and then push the revs even higher?

Harry