Ran the truck again today. Went ahead and hit run flat immediately after it started. Run flat and the highway light flashed together for a short time. After that, it went back to just flashing the highway light. I stayed in the truck while it was running for 10-15 minutes. During that time, the highway light never stopped flashing. There was also no honking. The valve on the floor would buzz for a while, then stop. Then buzz for a while, then stop. It did this the entire time.
I went back into the house and let the truck run for another 10 minutes while I cooked a pizza. During that time, it may have honked once.. I can't be sure though. After the additional 10 minutes of running I went back out and shut the truck off. Right as the engine shut off the truck honked. As I went around the back of the truck to go over and open the air drains, I could hear an air leak. It was coming from the passenger side front-rear tire. It was a very strange leak that didn't make sense to me.. I couldn't feel any air leaking anywhere. It sounds like the air was leaking out underneath that hexagonal nut piece that goes into the tire. But like I said, I couldn't feel any air anywhere. It sounded like the air leak was inside the tire, which I thought was weird. None of the other tires were making any noise. I went back into the house, ate my pizza, and when I came out 10 minutes later the "leak" had stopped. I double checked, and it was not because all of the air leaked out. There was still a significant amount of air in the system. At that point I opened the drain valves, released all of the air, and went back into the house.
Anyone else ever experience this issue?