I have strong backfire from approx 1600 RPM to idle speed when I decelerate down with the clutch engaged. When it reaches 1600 RPM it bangs from the silencer. I know its too much unused fuel getting into the exhaust. There is no difference if the engine is cold or at running temperatures. I did try with changing settings in the fuel map, fuel timing but with no effect on backfire. Any hint what I should look at, trying to get rid of the popping? Otherwise the engine runs very fine no issues. Its a Duratec 2.3, SBD TB's, custom exhaust, 260hp. thks for Your advice Hanns Per