I'm new to the site and I've already searched the forums and found that many other people have had the same problems. However, I didn't really see a fix to the problem.
My '04 WRX has had steering issues for 1 month now. The power steering "cuts-in and out" while driving. I thought I had a bad power steering pump, so I replaced it. That was not the problem because it's still doing it. I've been studying the ALLData steering diagrams, trying to figure out how the steering is setup and what might be the possible problem. There's a control valve that seems to control fluid to all the necessary parts. Could this be bad? Also, the parts stores lists a power steering filter available. Where does that go? Could it just be my filter is clogged? My car has right at 80k miles on it now.
Has anyone had this problem? Again, the symptom: Steering tightens and loosens from side-to-side while driving. This is starting to get annoying. and I'm sure it's not safe either, as my wheel doesn't always straighten itself out after a turn.
I've had it on the lift a couple of times and cannot find any visible signs of anything wrong. The belt seems fine, it was replaced 10 to 15k miles ago when I changed to lightweight pulley, still tight and doesn't squeak. The steering fluid is good, not leaked anywhere and not foamy.
Also, when I hit a pothole or bump at low speeds, I can hear something rattle, like a loose heat sheild or something metal. I've tracked it to the left front wheel, a small knock when I move the wheel by hand back and forth. This may relate to the steering problem.