I've been having weird steering wheels vibrations recently. The issue first showed itself way back in 2019 just before I put the car away for winter. The steering wheel just started to move slightly left and right on its own. I pulled over into the parking because I thought the lug nuts were loose but when I checked them, they were all torqued down. I also checked the tires visually for any bubbles but saw nothing. I started driving and the issue went away, so I had thought maybe something got stuck to one of the tires and it came off before I could check, so I put the car away for the winter.

Fast forward to 2020, where I drove the car for about 12k miles and the issue didn't show up even once.

Fast forward to 2021, the issue showed up 3 out of the last 5 times I drove the car. I start to drive the car normally, everything seems fine, but suddenly, the steering wheels starts to vibrate. It is definitely dependent on wheel speed. Every time this happens, I pull the car over into a parking lot to check what I can, everything seems normal. I start driving again and almost always the vibrations stop. This one time I was paying close attention and I noticed that it started after I braked quite hard so I pulled into a parking lot after driving for a mile or two and noticed that the driver side front caliper was slightly warmer than the passenger side front. I start driving after chekcing and as usual the vibrations stop. I dont think the vibrations go away while I'm driving, they only stop once I stop the car completely and wait a couple of minutes.

Googling the problem seemed to indicate warped calipers (unlikely since the issue wouldn't be sporadic), sticky caliper, worn out steering guibo, and maybe something wrong with the steering rack itself. I am inclined to think sticky caliper due to the difference in caliper temperature but I am not certain. I am planning on bleeding the brakes this weekend as a first step but wanted to check with folks here to see if they have any other ideas/suggestions?

Thanks!