The steering wheel on my '89 Civic vibrates noticeably left-right, like
the car is alternately pulling in both directions, when going 50 MPH or
better. At lower speeds I don't feel it (or it is slight enough that I
don't). I checked the tire pressure, and they're all good. Is this an
alignment or other issue, or just the age of the car showing?

Thanks,
Matt

PS- Thanks to previous posters for the info on my oil consumption
problem; after I replaced the PCV valve, head cover gasket and switched
to Castrol Syntec the consumption dropped off the table, it's very
slight now.