also bad connections become more apparent when there are more things that have to have their positions altered, eg cars at a start, once your up and running and the field is a bit spread you don;t notice the issues so much.
as was said though check with your ISP, my ping to iracing went through the roof a while back, it was that bad the australian servers were a better ping, and i almost changed ISP but thought to contact them first, turned out they were doing some ongoing maintenace / upgrades and as a result were having to route some american traffic via a roundabout route, two weeks later, a week earlier than predicted, it improved and was actually 10% better than it had ever been.