I have a suggestion. Check the rubber bump stops in your front. What you're describing sounds similar to something that happened to mine... Everything was find until I'd take a hard left turn, then the car would go all Christine and try to murder me. I'd jack it up to check the problem, find nothing, and it would then miraculously be fixed until the next hard left turn. Turned out the right bump stop was gone. I replaced them both and the problem never came back. Apparently the suspension would get into some kind of a bind when it traveled further than it was designed to, and wouldn't pop back out until I raised it.
Drew is a genius! Looks like you hit it on the nose Drew! I jacked it up a while ago and got under it. Checked both bumpstops, sure enough, the one on the passenger side is broke. It looks fine until you push it with your finger, then it swings away. That explains why it only does it one direction. Going to order one for both sides from RockAuto and replace them both. Will update when I get them on!
Awesome! I'm glad I could spare somebody what I went through with that. Such a simple problem that leads your mind off into every direction except the right one.
Update # 1 OK, I got the bumpstops from RockAuto today and installed them. Did a little short ride around, about 10 miles total. So far, everything seems back to normal. No sudden pulling, no surprises. Have a longer trip next weekend when I go to the monthly cruise in, so I will know more after that trip since it is on a twisty, bumpy road. Still looking like we found it! :bananaman
Update again: Well Gene, you can stop being skeptical! Replacing the bumpstops cured the Christine effect! No longer does it suddenly dart to one side. I guess it's like Drew said, the suspension would travel too far up and bind up, then, when it let go, it would take off in a new direction! Since the car is lowered, and has less travel than a stocker, the effect comes on earlier. I'd almost be willing to say you might never have it happen on a stock front end with uncut coils. It's smooth and straight now, even when you get it up to 110 mph like I did tonight to get away from a tailgator . Yeah, I did! I was doing 60, and a Ahole wouldn't get off my bumper, so I mashed it! He stayed with me to about 75, then it was bye bye! Kinda surpised myself that I had gotten up that fast. It was a smooth, steady pull, and was still picking up speed when I let off.