When I got my 85 300TD-T about a month and a half ago, it too was VERY sluggish when cold, it would barely move off the line (though I can't honestly say any rocketship ever arrived). After lots of normal maintainence type stuff (valve adjustment, diesel purge, full fluid changes) it's still sluggish when cold, but it can at least get out of its own way.

If you haven't already, do the full maintainence routine. Just my 2 cents.