The emission control systems on our cars are too complex to make specific suggestions without more info about your car: N/A or Turbo? Original to CA or from another state? Stock factory engine and emission controls or modified? If modded, what? Did it pass for you in the past? If so, any changes, performance problems or major repairs since then?
Some general suggestions of things to do or check:
- All vacuum hoses for leaks
- Throttle position sensor setup
- Idle speed / idle mixture setup
- Run a tank of gas w/ fuel injector cleaner
- Just before the test, give the car a good run & have it tested right away