Recently purchased my '05 Grand Prix Base the other day. At the dealership I was told the problem with the check engine light was a loose gas cap and it was fixed. Once I filled my gas tank the light returned. Using a home ODB-II scanner I found Check Engine Code: P0420 to be the problem. Everything seems to run fine and it has 128,000 miles on the engine. I am told it most likely an O2 censor, but I am worried it might be more. What should I do and do I need to worry, or this is a small matter to be solved when I can afford it...sooner rather than later of course.
Thanks in advance!
...also, does anyone have a repair estimate for this? I am broke after totally my previous car and trying to budget.
