Sorry to branch my problem into two threads but the other thread was about a different question.
I had my 2nd smog test after cleaning the throttle body and all the sensors and the NOx levels were almost identical. No CEL, not driveability problems, no throttle hesitation, nothing to indicate a problem other than the high NOx levels and the failed smog test.

I took the car to a test only station this time and the tech told me that it sounded like there was a vacuum leak but he could not figure out where it was coming from. I looked it up on google and this site and learned that a vacuum leak can also lead to lean burn and high NOx levels, but none of the posts were cavalier specific so I thought I'd pose the question to you guys.

Which vacuum line is most likely to leak, are there more than 4 vac lines in the engine (those connected to throttle body), and what's the best way to figure out where the leak is?

Thanks a bunch.