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 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.
So that's that. I was able to find someone with a used exhaust for $250 that I can use until I save up enough cash for a better one. I just needed the O2 sensors, the car needs three of them. Toyota quoted my mechanic something over $300 for just one of them. I was able to find all three aftermarket sensors for $300 total... nice. So this may end up costing about $1000 to repair instead of $3500 that I was quoted originally. Still not a great deal considering the part that failed is supposed to be covered by my warranty.