Q: I have a 2009 Pontiac G3 with a 1.6-liter engine. The “check engine” light came on about six months ago showing a P0420 catalytic converter efficiency code. Since then I have replaced both oxygen ...

Thanks to modern fuel injection, the engine computer has extremely precise control over the proportions of the air/fuel mixture inside the cylinders. A countless number of sensors around the car tell ...

Q: I have a 2010 Honda CR-V. Last month its check engine light came on. I'm a retired mechanic and my scanner found code P0420 — catalytic converter efficiency. I tried a catalytic converter cleaner.

Answer:That's a new one for me, and I cannot see it having any effect on preventing a P0420 DTC, but it is illegal. P0420 indicates the catalytic converter has lost its efficiency in reducing harmful ...

I have a 2009 Pontiac G3 with a 1.6-liter engine. The check engine light came on about six months ago showing a P0420 catalytic converter efficiency code. Since then, I have replaced both oxygen ...

DEAR CAR TALK: I have a 2008 Toyota Prius with 95,000 miles on it. About 18 months ago, the catalytic converter was stolen, and I replaced it with an aftermarket converter for about $200. All was well ...

I just recently got some decent work done on my lovely 97 Firebird (V6, Y87). New wires, plugs, coils, and 02s. Well, I noticed my check engine light came on today. Fellow at the AutoZone said it was ...

Question:I have a 2001 Nissan Pathfinder with the 3.5-liter V-6. The check-engine light came on, and I had code P0420. I was told it was a bad catalytic converter, so I went ahead and replaced it ...