Stalling out at 2,000 RPM

[James Adelman]

I have a 5.7 EFI Volvo Penta in my 2000 Chaparral. It keeps bogging down when I reduce RPM to around 2,000. If go into neutral and then throttle up at will rev past 2,000 to its normal range. When I slow down and hit around 2,000 that's when it bogs down. If keep it in neutral and rev it up and down, even at 2,000 RPM,,no problem. Only when I am running engaged . Please help?