...
I've got a brain tickle about someone doing something bizarre with his front stock swaybar that caused a similar problem but I just can't recall the specifics. It was one of those "hey, what's causing this" type thing, lots of folks gave answers and then he came back and said never mind, I was being an idiot. Also didn't say what he was doing wrong.
The one I'm thinking of had the front sway bar catching the frame from below and not allowing the shocks to compress. And I think the front ride height was high.