Do you sill have a cat on it? If you do then there is no reason to fail....

When was your last tune up? What fuel do you run and how long did you let your car run for befor you took the test? I let my car run for 1 hr befor, drive there, wait in line for 35-45 min with my car running, and I passed with flying colors- 94 Civic EX D16Z6: CAI, Headman Header, 2 1/4 Pipes, free flow cat, and Flowmaster muffler.