Last year I installed 2 new rear Khumo's on my '95. Pep Boys called to ask me to sit down while they told me how much it will cost to replace my inflation sensor strap that was broken in two. They said it was that way when the removed the tire. About $200 cost from my local Chevy dealer. After looking at the sensor I believed them. It was very scuffed up and looked as if it had been rumbling around inside the tire for years. Actually, what had happened is that the guy I bought the car from had that tire plugged just before I bought it (about 10,000 miles earlier). I got to thinking........... you know, I never could get a good balance out of that tire, and it was all cupped out and worn severely. Each time it was balanced the sensor would be held out against the tire to allow the balance to be done. Great, but each time I drove off, of course the sensor and shifted and tumbled to a different position sending the wheel out of balance again! The out of balance condition was not THAT bad, or I would not have lived with it for so long, but it was a nuisance.
I determined that the strap, in fact, had been broken before Pep Boys touched the wheel. To correct the situation on my dime, I picked up the sensor assembly and glorified 16" hose clamp that mounts it to the circumference of the inside of the wheel. I straightened the strap out on my bench vice (the former tire guy had literally ripped it off when he patched the tire) and took it to a local welder for a $19 weld to get the strap back in order. Pep Boys reinstalled and all was fine.
This may not be the cause of your problem, but I would have felt terrible if I had blamed the good folks at Pep Boys, and then found out that the strap had been broken for years.