my ses light has been on all the time first it was the gas cap i got a new cap then now about 100 miles later it is still on went to autozone had the codes read now it says the cat failed i had the cat replaced after i bought the car in july of last year could the 02 sensor have failed i have to have the car inspected at the end of the month thanks to the great state of texas it wont pass with the light on

https://www.gmforum.com/showthread.p...86#post1390979 Start by checking the EVAP system for leaks. Vacuum leaks in this system are a pain to find. Inspect the exhaust system for leaks.