This weekend I had the tires rotated and every thing seemed fine until Tuesday morning, when my steering wheel decided to be off center about 10deg to the right. Monday night when I drove into the driveway I felt a slight shift in the steering wheel, but I usually feel all kinds of strange things so I didn't think much of it (this is the only clue I might have for the problem). Tues morning I aired up the tires (the shop like to lower the pressure) and on my way to work I noticed the wheel off, but everything else seemed normal (tracked straight and no pull). Tues night I rechecked the tire pressure and the front tires were equal pressure.

What can shift/slip/move to make the steering wheel off center?

 

my guess would be the rack an pinion moved in the mounts.

 

Did you get a front end alignment after your tire rotation ??
They are supposed to center the steering wheel before they make adjustments for caster, camber and toe.
Just asking

 

My guess would be a bad rack mount.

 

No alignment. I was thinking maybe the rack shifted also, but then how could it with it being pinned on the left side? I'll have to inspect.

 

Just to close the loop on this... I couldn't see anything amiss with the rack or tie-rods. I took it to the shop for an alignment and they said the toe was out on both wheels, and the front end parts were okay.

 

That is a common symptom of a shifted rack

 

Try this. Remove skid plate so you can see the entire steering rack, have someone turn the wheel while you watch the rack bushing movement @ the passenger side mount.
Rack should not move at all. You will also see some black paint rubbing off or missing from the rack cylinder if it has been doing it for a while.

 

So how does the rack shift? Bad bushings on the driver side? Do you mean the rack tube or the rack gear shifted?

I did what you said, Tainter, and the only movement was a tiny bit in the vertical direction. I had the front end jacked up during this test. The driver side barely moved.

I've replaced that passenger side bushing a couple of times. Maybe it is time to replace it again?

 

Try it on the ground. That's when the pressure is on the mounts. Hope it's just a bad rubber bushing holding the cylinder.