Back in MI I had a very hard time arguing w/ a stealership and finally gave up. It was always pending code though, never elevated to orange so to speak.
I didn't have any performance issues, just the same code as you and it always took very loooooong to complete readiness tests. After I moved to NJ the car passed emissions w/ flying colors (which means nothing, cause it would do that even w/o precats) and finally ended its life on insurance company tow truck all w/ original precats. So I'm guessing may be dealer was right after all.
I know what I'd do if my '98 starts popping 420. Hint: it has nothing to do w/ emission warranty.
