I need to get my '92 SSE */c smogged soon, and I'm a bit concerned that it may not pass because the test results from 2007 showed CO% to be almost at the max allowed value for the 15MPH test, and the HC measurement was also close to the max allowed value.

Here are the numbers from 2007:
Test-------RPM--%CO2--%O2-----------------HC(PPM)--------------------------CO(%)----------------------------NO(PPM)
15MPH--Meas--Meas---Meas-----|Max------Ave------Meas|-----|Max-------Ave-------Meas|-----|Max-------Ave-------Meas|
-------------1755--14.5-----0.1---------112---------31--------90----------0.72------0.10------0.70---------778-------237-------152

25MPH--Meas--Meas---Meas-----|Max------Ave------Meas|-----|Max-------Ave-------Meas|-----|Max-------Ave-------Meas|
-------------1707--15.0-----0.1---------86---------20----------20----------0.60------0.09------0.00---------717-------199-------258

What'* most odd (to me, anyway) is that the CO% was measured to be 0.0% for the 25MPH test and that HC was the same as the average value at 25MPH. Does that make sense to any of you?

Also, what could cause the O2 to be 14.5% at 15MPH but 15.0% (correct) at 25MPH?

From what I've read on different forums on the web, it appears that the engine was running rich at the time of the test because CO was higher than O2 and because HC was also close to the max value. But the fuel economy at that time averaged 19 to 22 MPG in mixed driving and that'* normal for this car.

There were roughly 40,000 miles on the O2 sensor (Delco) at the time of the test, and roughly 30,000 miles on the cat (Carsound cat that I had replaced just because there were roughly 130,000 miles on the OEM cat at the time).

Since the time of the last test I've replaced the plugs, wires, some of the vacuum hoses, BCS (failed twice), BCA (leaked vacuum), and the TPS, and yesterday I replaced the O2 sensor (new Delco AFS20) and the air filter.

Any ideas on what else I should do to help make sure that it'll pass the emissions test?

Lastly, how many miles do I need to drive after I replaced the O2 sensor? I didn't remove the battery cable to clear the ECM...should I have cleared the ECM, and if I do that, how many miles do I need to drive it before I have it tested?

Thanks.

Well, for those of you who may be interested, I changed the oil and filter and took it in for the smog test yesterday afternoon, and it passed with flying colors. As a matter of fact, the tech made it a point to tell me that the car had very low emissions. The CO% was almost 0% yesterday, and I believe it'* primarily because of the new O2 sensor.

Here are the numbers from yesterday:
Test-------RPM--%CO2--%O2-----------------HC(PPM)--------------------------CO(%)----------------------------NO(PPM)
15MPH--Meas--Meas---Meas-----|Max------Ave------Meas|-----|Max-------Ave-------Meas|-----|Max-------Ave-------Meas|
-------------1744--14.6-----0.2---------114---------31--------41----------0.73------0.10------0.02---------785-------237-------343

25MPH--Meas--Meas---Meas-----|Max------Ave------Meas|-----|Max-------Ave-------Meas|-----|Max-------Ave-------Meas|
-------------1695--14.6-----0.1---------88---------20----------26----------0.61------0.09------0.01---------724-------199-------271

Thats good to here.I'm an inspector here in PA. thows number look good.Here in pa we only run the 15mph test.Not 15 and 25mph dyno.