Skemper,

Usually a loss of of power in a Diesel is not enough fuel getting into the cylinders from plugged fuel filters. But you wouldn't get any black smoke if filters were plugged.

It sounds like the Turbo is not working and you are getting a too rich mixture because the engine is expecting more air to be pushed into the cylinders by the turbo. There is also control circuitry that varies the amount of fuel delivered by the injection pump and that could be malfunctioning.

See if you can take off the intake air plenum from the air cleaner to the turbo and see if the turbo spin freely. If it doesn't spin freely, that is your problem. There are also vacuum/pressure lines from the intake manifold thru a electrical box and to the injection pump. Make sure these lines are not plugged or leaking.

P E H