After you do a tune up or whatever, before you go take the test take
one bottle of dry gas (isopropyl alcolhol) and dump it in the tank. I
haven't had a car fail yet..

I have a 89 Cutlas Cierra w/ 170k and it passed with flying colors and
I don't do squat to it.

Chas

Sharshera wrote:
> I have a Nissan Stanza 1991. It passed Emission tests since I got it in
> 2001. But this year it failed in all the three tests NOx, HC, and CO.
>
> The car has 197K+ on it.
>
> I change the O2 more than a year ago (I got the BOSCH universal O2
> sensor on it). Oil was due to be changed by the time of the test but I
> didn't change it. I have never changed the CAT on it. By the way, does
> the CAT get fixed or they just need to be replaced? (Excuse my
> ignorance).
>
> I noticed before sometime before the test some blue smog coming out of
> the exhaust when I start it but it goes away in a little while.
>
> I had put in the fuel tank a bottle of some Smog Reduction additives.
> It was already in the tank the car test with.