Actually, there is no such thing as a "protection mode", it has a minimal "limp in" mode with some preset sensor readings that are not very flexible. It is meant to get you home or to a service facility to get repairs. What you are feeling is lack of engine vacuum to pull in raw fuel, since the exhaust has no where to go and does not burn "again". I think you are on the right track, but, something usually cause a converter to go bad. It doesn't happen on it's on. To rich a fuel mixture for extended periods usuall the culprit. Raw fuel burns in the converter and superheats, causing a catalyst meltdown. I have also seen bad diverter valves cause meltdowns. If your car has a smog pump, undo air hoses off emission tubes that go to manifolds and run car. If you have air coming out while idleing, the valve is bad. Good Luck! [8D]

 

mech 259, how about the fact that it's the original converter, and in our area we have cold winters and lots of moisture.

 

Should not have anything to do with it. Moisture is just a byproduct of the warm exhaust contacting the cold metal and does not make the converter to hot.

 

I guess I didn't state it correctly, with all the salt on the roads up here, under carriage rust is excelerated, I already have the converter on the way, with a big whole in the one on the car, it won't hurt to go ahead and replace it.

 

LOL, I'm sorry. Misunderstood you. Have you tried vacuum gauge on the manifold vacuum. It will be a dead giveaway for exhaust restrictions. [sm=drooldude.gif]

 

mech 259, looks like Ill have to starting buying test gear for my vette, I guess I'll store it out in my shop in the garage, next to all of my tv test equipment, and to answer your question, no I don't have a pressure gauge, I'll have to stop by pep boys and pick one up.

 

thanx for all the suggestions, the final remedy was a clogged cat converter, the thing flat out flies now!!!!