Peach1303, okay i had the same ordeal, i changed both my catalytic converters on my Z28 and it was after the light came on, problem solved, but now you face another problem, get a tune up for your car, all the old components will dirty up your new converters and age them fast.

 

i just had both of my cats converters replaced for free cause the car was under 81,000, gm done it for me,,,of course i had to pay 50 bucks for the computer hook up

 

They shouldn't have charged you anything...have two friends who had a cat replaced, two different dealerships - neither was charged a penny. Call the 1-800 GM service number and demand your money back.

 

That happened with my 02 Z28 as well. The manual says that it can be caused by a change in the factory exhaust, intake, and tires. I have changed to all three of these. Do you think this is the problem or should I have it checked out still?