RED HOT CAT & P0300 (random misfire)

Pleased to report no smell and no check engine light driving back home from work.
 
The stalling and "rich" CEL flash returned today.

I've been reading several posts and threads from various sources, and I think I've found a lead. Upon reading this thread http://www.mazdas247.com/forum/showthread.php?123732861-Canadian-EGR-valve-exposed I realized that this stall usually happens when I drive onto a bridge that is situated directly over a large lake. The car is always warm at the time that I make it to the bridge, and the problem rears its ugly head with perfect clockwork as soon as I drive onto it. I used to think it was voodoo, until I read that a faulty EGR valve is most deeply and negatively affected by MOISTURE!

Thus, the perfect timing of the problem coinciding with me driving onto a bridge directly over a vast lake makes more than perfect sense.

It looks like a new EGR valve is in my future.
 
So I changed the coil packs, boots, and wires, and boy is my face red. :o

I'll hang on to the EGR for a couple of days after it arrives, just to be sure. If the problem doesn't return, I'll be returning it. (flash)

It was nice to put the bike to good use, though.
 
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Dont feel funny coil packs and plugs are the worst haha thats how I fried my precat got a misfire didnt take care of it soon enough than it went now its gonna be hard to get it to pass smog haha
 
I'd replace the Catalytic converter and the main O2 sensor. From my experience with the P300 Code, then followed by a damaged Catalytic converter is the Coil packs going out. Its sucks replacing all this but, Coil packs, plugs, and wires, cats, O2 sensor. If money is tight I would at least start with the ignition problem and correct that before buying the new Cat and possibly torching the new one b/c you haven't fix the Misfire.
 
A week or two.i fixed the misfire new plugs and wires.but didnt think about coils.about a month went by than the check engine light came on p0421.
 
Well if your cat is glowing red hot I would certainly start checking to make sure it is not plugged up. That is really the only good reason as to why it would be glowing. Kinda like taking a torch and shooting it into a stainless steel pipe..... flame comes out the other end VS. taking a torch and shooting it into a pipe with one end capped off...that heat is gonna build up and blow back on you. Hell on the engine too.
 

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