300TD: No power when cold, fine when warm

[aliaswitheld]

(My first posting; hello everyone!)

The details: 1985 300TD Turbo
Cool Weather in Michigan (35 degrees F)
Car starts immeditately, BUT:
No power: full throttle barely creates movement
Once 1500 RPM's arrives: ROCKETSHIP acceleration
After 3-5 minutes, problem is gone, drives normally.

This problem is not affected by EGR disabling/reconnecting as tested during the last month. Once the car is warm, it drives it like a gas car. I have never fooled with the ALDA, but perhaps a past owner did--I have only driven one winter in Texas, so cold weather has not been a problem before.

Is this as simple as a vacuum line seal someplace? Where?