An extra worry. Just when you thought you had enough to worry about, your car dash tells you that you’re not quite up to pressure.

“Oxygen Sensor, ” it said, with the bright red light behind it. I’d driven this car 30,000 miles without ever seeing this strange message. Now, as I embark upon a long, Friday night trip to see my sick wife and lonesome daughters, after I had put aside the local financial woes, beyond the snowy weather, now I see a warning from my car as well.

“Oxygen Sensor.” I ponder the meaning of this. I am in the mountains, at altitude, low oxygen. Maybe the carberator is running to lean? Then again, the odometer does say 179,010.

Will I overheat and burn the engine? Is it too rich? Are carbon monoxide and other lethal gases leaking through the firewall? Should I bail out?!

“Oxygen Sensor.” Here’s one more little thing to worry about. Thanks. Glad you didn’t miss an opportunity to make my life a little more — complex, uncertain, worrisome.

Some psychologists say it’s the little stresses that really get you, not so much the big crises. Gnawing away at you. Maybe the final collapse comes with one last straw, rather than a big push. One thing I’m sure of: I really didn’t need this extra worry right now.

I continue to drive. In Truckee, I poke around under the hood a little, before I pull onto the long highway home. Loose connections or stuck valves are not going to provide an easy answer. It’s not even a familiar danger, like a low gas tank. Then, at least, you know where to focus.

Oxygen Sensor?! I’ve no idea, and staying put would not do well with the other, known and identified worries that I’m trying to focus on. My family, my wife’s birthday, a Papa who has been gone for over a week. So I push on.

Push on, into another unknown. All I can do is listen, watch and respond. She seems to run as normally as ever. Smells and sounds and feel are all about the same. Keep going until something changes, until some more obvious alarm sounds. Hold your course.

Maybe most alarms are … not false, but minor. We miss the bus. The world does not stop. We catch another one. Overall, the world does not change noticeably for our revised schedule.

A deadline is missed. A product is delayed. A friend has to wait 45 minutes for you. Yes, avoid that if you can. Minimize it when it happens; but move past it. Keep moving. And still, keep an eye on the dash for warning lights.