Sienna steering wheel vibration

I have a new to me USED Toyota Sienna 98. Bought it at 76k. There has always been a fairly faint and rare pulsating vibration/wobble in the steering wheel. It has gradually been getting more pronounced, even to the point my wife ‘discovered’ it. So far it really does not detract from driving or steering and remains in the realm of “minor” problems. My guess is either a problem in 1) power steering, 2) tire balance or alignment 3) tire defect 4) bushing

any ideas on how to narrow it down? tnx

Nothing quick, just eliminate the possibilities one at a time.

BTW, you left out warped rotors.

Is one of the tires worn unevenly?
Try moving one wheel at a time to a different corner and see if the vibration follows it.

Ensure the air pressure is at the recommended pressure in all tires. (follow the door jam sticker or plate for the proper pressure)

Is the pulsing consistent with a particular speed or does that not matter?

Tires are the first thing to check. Look at them. Is there abnormal wear? Cupping?

Rotating the tires might be educational. If the vibration stops/changes/moves, then you have something to go on.

Proper alignment and wheel balance is critical. If you suspect anything other than perfect, have them done.

I’d suggest warped brake rotors, but you didn’t say this “pulsating vibration/wobble” occurs under braking.

thanks to everyone for replies, the shaking does not occur during braking. Braking is smooth, even perfect feeling with the car.

I have noticed something similar with my mother’s 2002 Sienna. It is ever so slight and I only notice it during hard acceleration. My theory is that it is the normal operation of a torque converter that is jammed into the tight space created by a high compression front wheel drive V-6 engine. I am concerned that your symptoms are becoming more pronounced though. If you don’t find anything by following the advice that others have already given, you might get the torque converter checked.

I also have a 98’ Sienna which within the last two weeks developed a front vibration problem. I did have the alignment done and rotate the tires before the vibration happened a couple of months ago. I jacked the front axle up and found both front wheels have some free play. If you grab the wheel’s right edge with right hand and left edge with left hand, there is no free play if you push or pull at the same time, but there is some free play if you push with your right hand and pull with your left hand, and vice versa. Is this normal? I also feel the vibration is worse and jumpy at highway speed. With local driving, you can feel the steering wheel is rocking left and right slightly. Any ideas?