Toyota fails to make good on warrantied part

So now I'm trying to get Toyota to honor my 8/80 warranty on the catalytic converter.  Besides the factory warranty, it also had an "Extracare" warranty, and it's a Toyota Certified Used car, so you would think this wouldn't be a huge problem to deal with.  It was.

Here's my story.

2001 MR2 Spyder
68K miles
Dealer: A-1 Toyota
	New Haven, CT

The Spyder was running perfect, until one day I'm driving home and it loses all it's strength and the check engine light comes on. I brought it to my mechanic (who I trust and was very close to where this happened) and he found the cylinders were misfiring because the ignition coils were burnt. He replaced the ignition coils, and gave it a full tuneup, and the car still had no power. He found the muffler was clogged up, so disconnected it and the car got all it's power back. He explained to me that the catalytic converter melted, clogged up the muffler, and the backfire from the exhaust caused the coils to burn out.

So I made an appointment at the local dealership (A-1 Toyota , New Haven Connecticut) and I spent 4 hours this morning waiting for them to diagnose the issue. They handed me an estimate for $3475.00 (+tax) to replace the exhaust system (including sensors, etc from the manifold back). The service guy said it isn't covered under the warranty because "something" caused the fuel to run too rich and melt the cat, and that's classified as an external force. I had used fuel injector cleaners, but not extensively, just normal useage along with a full tank of gas on top of it. I had never put any octane boosters into my gas, or anything like that.

I called Toyota Customer Care and told them the story, but they rely on the dealership to diagnose the issue and cause, so that doesn't help at all.

I've asked my mechanic to speak with the dealership and try to reason with them the logic of the situation. If the dealership will admit that the catalytic converter was the root cause of this, then Toyota Customer Care says they will honor the warranty and replace what needs replacing.

I called the Service Manager at A-1 Toyota. He explained his theory that the fuel/air ratio was too high, and that cause the catalytic converter to meltdown. He stated plainly that he will not budge and will not cover the work under warranty. There was nothing further I could do. I ended up buying a slightly used exhaust from a fellow MR2 Spyder owner for a couple hundred bucks and nominal installation charge by my mechanic.

A couple months later, my engine completely died - I believe due to the same stress that caused my ignition coils to fail. I brought it to Toyota of Wallingford, and they took great care of me. The block had to be replaced, they used all new parts and they honored my warrantly without any issues what-so-ever. With the new engine block and exhaust, there haven't been any issues with the Spyder since.