Is there anything I can do, without the help of a mechanic, to lower my car's NOx emissions by ~60ppm?
My '93 Cutlass Supreme only just
failed the NOx part of its required emissions test. (Driveclean
.) It passed the HC and CO no problem.
To get a pass for the NOx emissions as well, every mechanic I've talked to wants to start with a $100 diagnostic test. If the emissions were way over, I'd do the test and get whatever repairs are required (clean air, and all.) But the mitigating factors here are: 1) it failed by only 60ppm, and 2) I'll be selling the car before the end of the year. I don't want to spend a penny on it if I don't have to.
Is there anything I can do myself to reduce the NOx emissions? I'm pretty sure the Cutlass Supreme's timing is computer controlled, so that's probably not an option. What about the fuel/air mix? Is there any way I can adjust that myself? Or what about simpler options like fuel additives?
Some other quick notes:
- I had the air filter and oil changed last week.
- The catalytic converter was replaced 18 months ago, and has less than 20,000 miles on it.
- For all the good it did, I ran one of those "guaranteed to pass" products through a full tank of gas, and filled up with Sunoco 94 before the test.