diesel pain

My truck starts ok not great but cranks twice or so after i warm the plugs. It starts and runs good Ill drive its for about a mile or so and the engine bogs out. It bogs and the power just goes away when i push the pedal the idel will go up slow be wont go anywere. Then ill pull to the sid of the road and the trucks idel will pulsate from where its sapost to idel to below idel but doent die every time. Then after a while it will run after that does any one else have this problem and what could it be its got 205000 on it it sould just be broke in. Its it inj. pump. ecu. plugs any one know please help.
Kory

Have you replaced to fuel filter ?