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Misfiring and glowing catalytic converter

14091 Views 7 Replies 6 Participants Last post by  sethbrawnl
We went out to start our 2000 Subaru Outback this morning and it started fine, but as soon as you put it into gear it has no power to move the car. Took it for a spin around the block to try to figure it out and when I got back the catalytic converter was glowing red.

I pulled the codes and got the following: misfires on cylinders 1&2, Fuel trim malfunction, and catalyst system efficiency below threshold (P0420, P0302, P0301, P0170).

What could be causing all of the above symptoms?
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Bad plugs, bad wires, bad coils, plugged injectors, just to name a few. Good luck.
How many miles on the car?

If your cat is glowing red, that is a very bid indication that it's plugged. It's not letting the exhaust exit, which backs up to the motor and causes all those malfunctions and misfires. Not sure if your state has inspections, but I ended up just gutting out and welding back together the cat in my truck. I did have an 02 sensor delete which saved me from staring at the CEL light.

A new cat is going to be some big $$, as they contain very expensive metals.
a bad coil will cause the front 2 or the back 2 cylinders to misfire just like yours. and 2 cylinders misfiring will dump a lot of unburned fuel into the exhaust and cats. the unburned fuel can, and apparently is, burn up in the cats making them red hot. and the p0420 is just saying the cats not working as it shaould, how can it with all that raw fule in them.

test the coil and the igniter. some years may not have an igniter, not sure about yours but the 90 - 99s do. the igniter sends power to the coil in halves. either the front half or the rear half. the coil sends spark to the cylinders in halves, the front or the rear.

my first guess would be the coil, but they rarely fail. plugs and wires are a much more common cause of misfires. but since you misfires match the configuration of the coil that it my guess. i would take it to a decent shop that can test your coil or buy a used coil and replace it your self. which ever fit your ability or your wallet. i suggest used just in caes the cause is something else.

but first i would make sure the plug wires are all tight and well connected and look alright.

how long since you did a tune up.?
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picture please! wow, red converter! on a 2000 that's very rare.

what's the history?
any major engine work or replacement?
So I got the misfire fixed today, canubaru you were correct and it was a bad coil. I went to the local salvage yard and got one used put it in and the misfire was gone. As soon as the misfire cleared up the glowing cat went away as well.
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