Q: I recently had my 1994 Toyota Camry XLE in for a front exhaust leak. The main symptom was a muffled noise coming from the front. After the repair, I still heard the noise, though not as bad. And call me crazy, but I feel lightheaded and dizzy, and I have a weird feeling in my throat.

Could they have done something wrong with the repair and now carbon monoxide is leaking into my car? Is there a way to test for a carbon monoxide leak in the car?

TOM: If you're still alert and conscious by the time you read this, go to a hardware store with your windows rolled down, and buy a carbon monoxide (CO) detector for your car.

RAY: For $20, you can get a battery-powered one. Put it in your car, let the car run for 10 minutes (without you in it), and then check the reading. I'm guessing you've got CO.

TOM: You've got all of the symptoms: Dizziness. Lightheadedness. Writing to me and my brother for advice!

RAY: Carbon monoxide is deadly stuff. It's also invisible, odorless and tasteless. So the only safe way to know whether it's present is with a CO detector.

TOM: The noise you were hearing was exhaust escaping, under pressure, from a cracked exhaust manifold under the hood. And it's certainly possible that your mechanic botched the job. He may have been wrong about where the leak was coming from, or he could have replaced your manifold with a used one that also was cracked.

TOM: So get it back to him right away. And leave all the windows down when you drive it there. After he fixes it, test it for CO again right there at his shop, before you drive it away.