My tenant reports that she sometimes has trouble getting her burners to light. She turns knob to light, the thing clicks, she says she sees the sparks, but there's no gas. If she holds a match up to it, it does NOT light. Eventually, it seems the gas does kick in. She thinks it generally happens after she hasn't used the range for a day or two.

I took apart the burners and everything looks very clean.

I personally can never reproduce this behavior. It always lights up no problem for me. I called a repair guy and he said that if he couldn't reproduce the problem, there probably wouldn't be anything he could do. I'm kind of stumped by this issue. I really don't know what to try next. Thanks for any suggestions you can give me.