Moving through a no wake zone slowly increasing throttle all is well until 2000 to 2500 rpms loose power into limp can also happen going up again slowly when I reach 3500 to 3700 again limp mode, always sounds alarm shows fault and sometimes fault fuel. Shut off engine and with key off I can move throttle up and alarm will start up again move it down and alarm stops. Shut off battery then back on start engine give alarm briefly but then runs fine until the next time. Today it was an hour later sometime never but never means when we return to port. Thanks for any help. P.S. Even the Volvo certified mechanic at $105. Per hour are lost.