I've got an 03 Camry with a little over 100k miles on it and on a trip this past weekend the check engine light came on. I took it by my mechanic who put it on a machine which indicated that the catalytic converter was the problem. He suggested cleaning the sludge out with a gasoline additive that he has created and is currently waiting to have patented. My question is have any of you had a similar problem with your Camrys and if so how did you resolve the problem? I have a friend who is a legitimate shadetree mechanic and he's suggesting to go ahead and replace the catalytic converter rather than attempting to clean out the sludge. The first mechanic is saying that the problem is probably being caused by my putting the lower octane gas in it, which I've been doing for the life of the car. When I purchased the car brand new in 03, there was nothing in any of the paper work, owner's manual etc, that stated that I should run higher octane gas in it. Is it true that the lower octane gas is bad for the catalytic converter? And, is it normal to have to replace a catalytic converter after just 10 years of wear?

Any help you can offer will be greatly appreciated.