engine bogs down when cold

[nepatternmaker]

97 DI PSTD, F350 CC LB 4x4. When you first take off with the engine cold, the truck will lose power to the point of stopping in the road. After you stop for a minute or 2 it will suddenly come back and take off again. it will do this 3 or 4 times, each time a little less severe. After that it will pull itself ok, but you can tell it's missing out fairly bad. After doing some research on here, it sounds like the UVCH may be the culprit and I think I have some to put on when I replace the glow plugs. But I haven't seen anything about the bogging and coming back thing with the UVCH, that appears to simply cause a poor idle or dying. I have the valve cover gasket harness, is that the UVCH, or is the UVCH another wiring harness altogether? Is there a temp sender on a 97 DI PSTD? I can see that being a problem, if my truck as one. Any other ideas? I'm learning this diesel thing, but it's quite a process.

Thanks
Dave