I had posted about a month ago concerning things that I could do to pass a failing emissions test. I passed on HC and CO, but failed on NOx. Well, I just went through my re-test and passed!! I'd like to share my data.

I tried doing my due diligence to find vacuum leaks but none surfaced, checked some of the other usual suspects and found nothing out of the ordinary. For fear of failing the free re-test, after which I would have to pay another $50 to test again, I decided to take some advice given in my previous post...

I plugged the vacuum hose that goes from the intake manifold to the ignition module with a small screw which, I was told, would make the ignition system default to a pre-programmed "lean" mode.

Below is my before and after data:

Before
HC: 1.96 Limit: 2.25
CO: 12.65 Limit: 23.74
NOx: 4.28 Limit: 3.25

After
HC: 2.14 Limit: 2.25 **close**
CO: 16.72 Limit: 23.74
NOx: 2.29 Limit:3.25

Thanks to Kane and gt6 for the good advice.

Bean
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'80 242GT 91k, '94 945T 110k