the ses light started going on last year a few weeks after my long tube header install and now I have to get the car emissions tested. The scanner says it's a problem with an o2 sensor on the left bank I think.

Should the car pass if I clear the codes and have it tested with no codes showing up? The SES light takes a long time to come back on.

I noticed that the scanner says incomplete for the o2 tests that it does which makes me think that it might fail at the testing station because of not enough information.

 

It's common, you could have a failing o2 sensor or an exhaust leak somewhere else.

Clear the codes and take it in. It may pop something before the ses comes on at which point they ask you to get a different gas cap or take it off then put it back on.

Years of that messing around and the 97' keeps getting it's tags renewed.

 

It may depend on what state your in. In NY I know you have to clear almost all the OBD2 checks. There is a little leeway, maybe one or two checks can be skipped. I forget where the o2 test come up on the drive cycle.

When you clear the codes it will set all those tests to un-checked. It may be less of a hassle to just replace the sensor.