Hello from Spain. Sorry for my bad English. I have written this post on the V6 forum, but perhaps it is better here. If not, I will move It. I have a 1990 Firebird 3.1 V6 that in smoke tests gave me a CO of 3.5 to 5 with a damaged catalyst. I installed a new catalytic converter and it got so hot that the color was bright red. In the forum they told me that surely it was getting unburned gasoline, and that I had to fix that first before installing the catalyst. And I'm waiting for the workshop to do it for me. In Spain the CO limit for a car with a catalyst is 0.5, or whatever the manufacturer declares, but I don't know where to find the manufacturer's value. They have told me that under the hood there is a sticker that says what emissions it meets, but I don't have the original hood, but rather the one from a 1987 5.0, and it only says that it meets the 1987 EPA regulations, but it doesn't give the values. Do you know what they are? thank you