Replaced 2 sets of coils AND Catalytic Converter in 3 months time?
 

OK, first of all, yes I'm back. I've been behaving but I'm back. Just make sure you search. :p:

Now, onto my problem.

Back in June I had failed coils...whereas my car had the CEL and extreme loss of power. Had the car towed to the dealership and replaced coils and plugs at no charge. And all was well...

Until two weeks ago. I noticed a rattling under the car and brought it in to be looked at. They decided the Catalytic Converter was faulty. OK. They give me a new one at no charge. However, the noise is still there. That was a week ago.

Yesterday, my car throws a CEL again and the same loss of power issue. Get it towed AGAIN to the same dealership, and they run the codes... P0300 and P0301. Faulty coils again inside of 3 months? Ok, they replace them again and all is fine....as of today.

I'm thinking something has to be causing a problem that I would blow through coils twice within such a short time, paired with a new cat. Any ideas on possible sources?

New coils are known to fail or causes misfire and welcome back.

My OEM Coils thought:
I was just reading a similar thread the other day (minus the cat issue) an a few peeps were chiming in about the OEM coils failing quickly if not failed shipped from the factory.

Rattle in Cat: Perhaps chucks of the old catalytic have been blown out and are now rattling around in the muffler somewhere? <shrug>

Did they inspect your plugs either time? Fouled plugs can stress the coils enough to cause them to fail and you would also burn out a cat if you kept dumping all that fuel in there.

The first time around they changed out the plugs. I don't know about the second time. Just not sure what else could be. Thinking maybe I upgrade the plugs to something other than OEM?