It makes sense. If that exhaust doesn't have any where to go... something is bound to fail. Chances are, a large portion of the converter broke loose and completely blocked the flow. I had a converter do this on an LT1... exact same symptoms; flashing SES and vibration relative to throttle. This was at 55k miles but I was aware that the converter was already on its way out.
Have you flooded your engine? 3x,xxx is was too early for a converter to go out.

 

Sounds like an awesome time to look into a midpipe

 

Hey, guys- if you don't have something useful and/or polite to say, then shut up. The whole "lets rag on someone just because we can" is getting very tiresome.

 

Darkwings, don't let the dealer screw with you about regular gasoline. Check the manual is says premium is "preferred" and regular (87 octane) is the minimum required. I actually had a Mazda lead mechanic tell me that regular gas was better for the engine if it ran fine with it. There is a lot of discussion about the grades of gas on here but bottom line is that running regular gas is not the cause of engine failure. If they did the recall and checked the engine compression that is the only way to be sure that the engine has failed and needs to be replaced. If they are saying replace only based on your symptoms...BS.

Certainly the cat seems to have failed but have they checked the coils? Another common issue that can cause the engine vibration. If you can get an engine replacement, fine. But on the face of it, I wouldn't buy in unless everything is checked and don't let them say that you caused the failure so it isn't covered on warranty based on running regular gas.

 

Thank you SilverStreak for taking the time to provide some useful information. Your answer about the gasoline matches my own conclusion after a great deal of reading (I sure know a lot more about octane now than I ever did). And it also matches what all my friends said.

The dealer had the car for an entire day before declaring the engine needed to be replaced. I have no idea how they reached that conclusion. I questioned the service rep about what happened and unfortunately he didn't have anything useful to tell me. His comment to me was "you ARE running it on premium fuel, aren't you?" to which I gave the classic answer that only a female can give: "I don't know, that's my husband's job, but I'm sure if it says that in the manual, that's exactly what he's done"
In reality, we tried various grades of gasoline when we first got it (plus did a lot of reading on this forum) and concluded that it didn't make any difference so we stuck with regular (87). We do buy the name brand gas (shell, mobile etc) and not the cheap stuff.
Thank you for pointing out what the manual says.


I am hoping to get the car back tomorrow. I will ask to speak to the mechanic since I'd like to get some real answers. The service rep said that they aren't allowed to open up the engine on a warranty replacement. They have to just ship it back to Mazda. So he didn't think they would be able to tell what went wrong. That sounds rather stupid to me...so that's why I'll try to talk to the guy that actually worked on it.

@architect: no, the engine has never flooded. It's run beautifully the whole time I've had it. It spends most of it's life running around in town. It doesn't get a whole lot of highway driving. I don't believe the cat exhibited any symptoms of illness except for a 30 second window last Thursday night when I pulled it into the garage. I thought something was strange but all I did was drive it 10 feet so it was hard to tell. It ran perfectly all day Friday until Friday night when it completely crapped out (as I've described).

 

Mazda does not allow any dealerships to open the engine, but even they do I think MOST dealerships have ZERO clue about how to fix them.

I have a feeling the issue could be resolved by a bottle of BG44K + Cat replacement. But most dealerships are loaded with morons and I guess the answer they got came from Mazda Tech line (Which is also loaded with morons)

Oh well ...

 

I got the car back today. Here's what the dealer wrote:

"Inspected and found #1 coil failed. Replaced both coils and plug wires. Arcing, internal failure, internal engine problem, lack of power, knocking at high rpm, replaced shortblock and transfered engine parts"

and then...

"Coolant leak after replacing engine. After engine replaced found coolant leak dripping under car. Found thermostat housing to be leaking. New gasket had damage on from factory. Replaced and refilled. OK now"

and then....

"vibration at idle after replacing engine. Inspected and found engine mounts rubber deteriorated. Replace engine motor mounts"

and then...

"rattle noise in exhaust after engine replaced. Inspected and found rear portion of converter came apart. Misfire concern, engine light flash, replaced cat converter."

finally, it passed their inspection.

The car seems to be running great now. But there's still a bad smell. I think there is either something leaking onto the cat (or there's some residue from the service that's burning off). I'll be watching to see what happens with it.

By the way, the basic warranty is still 4 yr / 50k miles. However the powertrain warranty has been extended to 5 yrs / 60k.

thanks to all who have responded.

 

Ha ha in the end they said you had a bad CAT.

They should have replaced that to solve your problem.