About a year after we got our 2019 Limited we noticed a low rumble or groan that gets louder and softer and repeats every few seconds. It happens when we are between 40-70mph. (At 75mph it's not there fortunately since that's our normal highway cruising speed.) It did this with the original tires. After we replaced the tires (BFG Advantage T/A Sport) and had the alignment checked I thought that would change, but it didn't. It doesn't matter what road surface we are on - asphalt, concrete, grooved concrete. It's loud enough that even my wife noticed and she normally doesn't notice these things.The pitch doesn't change with speed. I'll be taking the car in for the fuel pump recall soon. Any ideas on what I should have them look for that could be causing this noise? We don't have roof rails, sunroof or anything that sticks out.