I had the same issue but "fixed" it by raising the idle slightly.
In my case, its probably slightly lower compression in one of the cylinders but it runs great otherwise so I forgot all about it.
In your case, it sounds like you simply have some physical contact somewhere from the work you did...
Looking for a set of OME 891 coils and am looking to get rid of my 890's for more weight handling. So, I'll either buy your 891's outright or will trade you for my 890's.
Cheers
Thanks guys. I called around and none of the aftermarket drums around me for the 4runner come with balancing weights. While I know I could get OEM's for twice the price, I'll live with the potentially less than perfect balancing of the Napa parts.
The word "need" here is subjective. Most people won't notice the squirmy feeling from the back shifting from side to side when going over bumps. I do because I've spent more time in souped up race cars with nearly zero suspension travel than in trucks.
Install the springs and feel it out for...
I don't have the diff drop. The 881's weren't too much taller than my stock springs to make me worry. The only thing that bothers me is the panhard rod pulling the axle to the right since the geometry is tweaked. It makes the rear end feel like its swimming or wiggling side to side over bumps...