Thanks Kerry for you helping me.

I think I have found the cure!! When reading others conversations about engine trouble, I discovered an interesting thing, it said !QUOT! "move the throttle up and down slowly three times!! I did and the problem disappeared!! Something about ECU/FADEC computer self setting/adjustment.

Another problem have turned up during the past weeks flying. I got flame out when going from full thrust to idle rapidly. There is no bubbles or smoke, just flame out.
Can it be I'm flying an F15 Eagle (former D/F) with large intakes and by pass, creating a ram pressure. Can the flame be "blown" out of ram pressure?
I have cured the problem temporary by slowing down stick movement (computer radio) and always using at least 10-20 throttle setting as a minimum.