Has any of your Bonnies failed a smog test, and if so, what was the cause/fix?

I'm asking because my '93 SSEi (140,000 miles) is due for a smog test soon (here in so. Ca.) and I just looked at the test results from 2 years ago and noticed that although it passed last time, the HC measurement only passed by 3 PPM on the 15MPH test. At 15 MPH it measured 114 PPM (max allowed is 117) and at 25 MPH it measured 48 PPM (max allowed is 67). Also, at 15 MPH the CO measured .31% (max allowed is .48%) and at 25 MPH it measured .12% (max allowed is .45%).

The catalytic converter was replaced last summer because it rattled when accelerating, and I replaced the O2 sensor with a new Bosch sensor a couple of months ago because the fuel economy was 12 MPG once, and it was a big drop from the usual 16-18 MPG. It seems to be back to getting 16-18 MPG again.

The engine seems to run well, just as it has since I bought it in 1999.
There aren't any error codes.
There'* roughly 2,000 miles on the oil, but I'm going to change it before the test anyway.

What else can/should I do to help ensure that it passes the test?

Thanks.

I use RESTORE Fuel System Cleaner. It comes in a silver, metal container and should be with the rest of the additives in your local auto parts store. It will clean out any carbon that you might have in the system. Run your tank down to almost empty, then add the container and fill up with premium (I know, expensive). Run that tank down and fill up with your normal gas. You should have no problem passing. You'll also notice a big difference in your acceleration and fuel economy.

Some of you noted that the 3800 engines reportedly ran so clean that GM didn't use an EGR valve on the normally aspirated '92 version.

So I'm hoping that the cause of the high (barely passed) HC measurement on my '93 (it has an EGR valve) was due to the old catalytic converter.

I'll find out today or tomorrow when I take it in for testing.