If the rough idle is only at start up I would have to agree on the glow plugs. I adjusted my valves and cleaned my injectors becuase I feel I should be getting more MPG. (Hate to say this...gulp...I was only getting 18 MPG)

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'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
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'72 Triumph T100R