Cat system

[kji]

I have a 1998 Sport with the 4.0 SOHC. It recently failed my state emission test, had repairs done, but the Cat monitoring system has not run yet. It's been over a thousand miles and it still isn't ready. Could someone please tell me the driving procedure to get it to run? Or suggest what the problem may be. The CAt circuit was ready when it failed the first test (the first time I've seen that in two years).