What controls the kickdown. I assume its a combination of things including vacuum, but in my car if you decel at 80mph, then accell slightly, but fast it jumps for 4th to 3rd then to 4th very fast. Like in less than a second. My last 4spd auto did not do that.

Is that adjustable somewhere, like a cable end to the TB. Its just a little too jumpy. At other speeds its fine. Slow accel it does not jump. If you punch it, it drops downa nd acts like it should.

 

Take the slack out of the Trans kickdown cable.

In the 928 the vacuum modulator only controls shift firmness(that's adjustable too, btw).