Q: Catalytic converter gets red and lost power

There’s only one thing that will cause a converter to glow red. That is too much air and fuel. The most common reason is the engine is misfiring. If your engine is shaking, and does not have power, it is misfiring. The catalytic converter is not at fault.

When you replaced your spark plugs and coils, you also should have replace the ignition coil housing. It is known to mechanics as the "battleship". Spark produced by the coils has to travel along metal tabs to reach the plugs. It is common for this part to fail, and when it fails the spark jumps to other cylinders causing the engine to run very poorly. Replace this housing.

If the engine still runs poorly, more diagnostics will be needed. Do not continue to run the engine before it is repaired. If you do, you may have to replace the converter again. If you need help having this checked, a certified professional from YourMechanic can come to your car’s location to diagnose the loss of power in person and pinpoint what repairs are necessary.