Sounds like the burner is not getting enough air, try cleaning the port where the air and gas mix. Look for little creepy crawlers in the port.

On mine, there is enough space to fit a thin pipecleaner and clean out the tobe leading to the regulator, and then to clean the burner opening as well. My grill is a Char-Broil and they have parts at Lowes and Home Depot. I don’t know if these are univeral, however.

Disconnecting the regulator from the tank, waiting a minute and reconnecting it can often sort this out.

When disconnected I’d give it a few taps with a hammer. In the winter, mine ices up occasionally.
I’d also blow some canned compress air at the vent hole and other important surfaces. I put a very light coating of oil on the seat to help things go back together and seal nicely.

Great answers, all. I tried the passive reset. It helped the main burners and we were able to do a couple racks of ribs yesterday. I’ll have to try the pipe cleaner/compressed air trick tonight.