Passing emissions

Have check the catalitic converter?
That helps a lot to reduce the emissions.

Your check engine light is on?
How about your oxigen sensor?
Your tires size?
Stock size? Smaller? Bigger?

(The dynamometer test equipment is calibrated to the "stock" tire size. Over- or under-sized tires will alter the speed calculations performed by the test equipment and may prevent your vehicle from going through the test since the machine won't sense the correct speed for your vehicle's tire size)
those small details affect the test.

In what did your car fail?
Gross polluter?
Functional?
Visual?
Tailpipe?