flattops

I have a strange intermittent problem with what feels like the left front tire has a bubble. The steering wheel will even move as if the tire has a bubble on the tread as it rotates. I stopped and inspected the front tires on both sides expecting to find a bent rim from a pothole and a sidewall failure as this has happened before. The wheel and tire were fine. I began driving again and the problem was gone. I rotated the tires when I returned home and noted no unusual tire wear in the process. Seemed the cheapest fix to eliminate the tire/wheel as a possibility. The car still does it whenever it wants to, then goes away. If it starts, I can stop and start again and it will quit. Fault is not speed sensitive. Happens around 40 MPH but not always and will continue under 20 MPH. My initial thoughts are wheel bearing beginning to fail. CVJ is a year and a half old but the outer boot is torn. No squeeling, popping or unusaul sounds at all. Whats your guess? I'm pulling it apart today to inspect. Grabbing wheel when jacked, it has some side to side play, not excessive, and almost no top to bottom play.