First, let me start by saying "YAAAYYYEEEE!" Now that I got that out the way, let me follow up with a Thank You to the forum.
Here is a recount of the issue: My '86 420 would be running fine, then, seemingly at random, would start to bog down when the accelerator was pushed. This most often happened off the line at a stop. I had to "feather" the throttle to get it up to speed. Once up to highway speed, it often responded well when passing.
Resolution: People had suggested a million things, like the warm up compensator (which this car does not have, it has some other complicated part name), vacuum leaks, and electircal. I actually went to order the compensator part and the parts dealer called back to inform me that the car did not have one of those but instead had another similar part. I described the issues and they suggested I try replacing the OVERLOAD RELAY and the FUEL PUMP RELAY instead first. Each part was around $100 and was replaced in less than 5 minutes.
I am happy to say the car has not given me trouble with the issue since. Very cool! This car is a lobor of Love. While it is in great shape, it is getting to the point where repairs are getting more regular. If it turned out to be one of the $2k plus items like the vaccum plate, it may have had to get retired. Glad to say I'm still driving ad loving it!