99 4 runner check engine catylitc converts bad?

My check engine light came on. The toyota dealer checked it out and said my catalytic converters are going bad. They want $1000.00 each plus labor. They reset the fault and I drove the car for another 9 months no problems. There is no poor gas milage or stalling. There is plenty of power and runs just like new. The check engine came back on again and I suppose it is the same problem. Who in there right mind would pay some $2500.00 dollars to replace something that is working fine. My question, is there anything else that could cause the sensor to say the catylics are bad or what? I asked the dealer and they said the sensor is working fine.

hm, well, catylitic converters shouldnt be too hard to replace if you can find someone who does that (non-dealership) like a friend who knows a lot about cars?

otherwise... i'd say those guys are trying to rob you.

If the problem only occurs that infrequently, I would ignore it.