I've been reading all kinds of threads and trying to use this search engine finding a whole lot of nothing and I'm getting impatient with myself.

When I first bought my 1987 4runner with IFS, it had a wicked lean to the passenger side that seemed to be originating in the front but effects the entire passenger side.

I replaced the body mounts and ball joints all the way around. No change. Frame seems good.

What am I missing here?

A friend passed me on Mount Baker highway and said it was a frightening sight.

 

Went through the same on mine, same side too, I read to adjust the torsion bars, it helped a little. Turns out I had a broken rear, yes rear, leaf spring. Check it out.

 

Yes, I've read the same about the torsion bars and I've adjusted those several times for different reasons.
If a rear leaf spring is broken, is it very apparent?

 

I just measured the distance between the rear shackles and the tow hitch and measured 9 and 1/4 inches on one side and about 10 inches on the other. The spring looks fine to me... the u-bolts aren't straight though. What does tis tell you?

 

Maybe a broken spring center bolt.

 

Do you have to remove the spring to find out
?

 

You ought to be able to tell whether the center bolt is broken by close examination of the center hole in the spring perch and the center hole in the u bolt clamping plate. Make a comparison of what you see to what the other side looks like if necessary.
Could be a broken spring leaf too, sometimes they are hard to spot if its not the main leaf thats bad.