1984 300D still very slow

I've followed along numerous posts on this subject and followed instructions where I could, but my car is still a DOG.

I have performed all of these fixes yet not realized much difference:
-Cleaned banjo bolt
-Replaced air/fuel filters (many times)
-StarBrite anti-fungus fuel additive
-Replaced some vacuum connectors (not the 3-ways, just the small pieces - I'm poor, but working on it)
-Replaced brake booster vacuum line - it had 2 broken nipples.
-Replaced vacuum switch levers (the two plastic things on top of the valve cover - whatever they're called)

The car is still very slow off the line, it takes a good 45 seconds to reach 60mph. It also wont go over 75mph, though last summer it hit 80 it wont do it anymore. I have to use the "accelerate" on the cruise control to get any real speed out of it. Without it, my car would not be usable at all. Sometimes it starts out in 2nd gear, and shifting in general is very clumsy. In Park I can floor it, watch the RPMs jump way up, then level off at around 1200 - but the accelerator is still floored.
HILFE! HILFE!

Forums

Chassis Model Number