Maybe I can throw something in, along the lines of the previous post. Please I am not trying to offend anybody's intelligence, but where knpowledge and experience do not give immediate answers, maybe lack of knowledge and experience from other area (off-road) may help.
What you described as symptom, sounds a bit like the flying rear. Quite common in off-road, in fact. Like driving empty pick-up truck. What I remember from my off-road days, the reason was always one: something was preventing suspension to give in on bump like it should. And from what I remember, again, what we were looking at were:
Springs:
1. Springs too hard - out of specs, too stiff.
2. Springs too short (e.g. worn) and suspension hitting the rubber buffers.
3. Springs too tight. I do not know how to express it in English - the spring "thread advance" is to small, the spring has no room to be pressed as the "layers" of rod the spring is made off are too close to each other.
4. Two different springs on each side.
Shock absorbers
1. Shock absorbers out of specs (too hard)
2. Shock absorber piston stuck
3. Shock absorber rod bent and stuck
4. Two different shock absorbers on each side
Suspension elements
1. One or more of the pivots/movement points stuck - movement is restricted
In Pagode we have the right axis movement - something may be stuck there, something prevents the spring being compressed, maybe something preventing change of length of the right axis.
I remember the simple test was to try to depress and start swinging each of the rear corners of the car. If one is noticeably easier to depress than the other - then the hard to depress one is to be looked at. That is how I figured I had upper outer pivot stuck in the front of my Pagoda - the side of the car in the front was harder to depress and to start swinging than the other.
Tyre pressure can contribute, certainly, as one of the other colleagues wrote, if it is too high.
This is what I rememeber on these topics from my offroad days....
Pawel
