Check your tires. I noticed on the 10 mile ride home today in our back-up/spare vehicle ('92 Jeep Cherokee) that it was noticeably pulling to the side. I could not remember hitting any potholes and just figured it was the fault of the bald tires. Later, I was watering in the yard and took a glance into the carport to find the left front tire almost sitting on the rim. Took the tire a mile down the street to have it repaired. I could not break the lug nuts loose with my star wrench. Used a breaker bar and the nuts were making that high-pitched squeal for the first turn or two. I'm afraid to oil wheel studs, so I just had to grin and bear the chalk screeching on the blackboard noises for a short spell. At the tire shop, the guy dunked the flat in a tub of water, marked the spot, then tried to remove the three fasteners attaching the plastic center piece with a pair of pliers. Nothing doing. He went looking for a tool to fit (maybe 5/16"?) but came back with nothing and started over with the pliers. I took the mini-socket sets from behind the seat of my '96 Dodge Dakota (one SAE and one metric) and set them down beside him. It didn't take him but a millisecond to figure out where to find what he needed after that. He broke the tire down and patched the inside. The tire has little/no tread and is maybe 15-20 years old. I try to keep speeds down below 50 mph and never drive this vehicle out of town because obviously you can't trust old worn tires like that. (Recently spent over $1,000 on two new sets of Michelins for our two daily drivers and I feel good about that). When the guy threw the tire into the bed of my pick-up, I noticed the valve stem cap was missing. After I pointed that out, he brought one over and screwed it on. He tried to charge me 60 Mexican pesos which is about $2.50 USD but generous as I am, I gave him 100 pesos (about $4.25 USD). Of course, in the good old USA I probably could not even find a tire shop at any price that would have been willing to repair a tire like that.