Took the car in for the emissions test earlier today and came out "failed". My NO levels look to be the issue. Was hoping some of you had already been down this path and could advise on items to try. All I have to pass is the 2-step testing procedure (ie. idle sniffer test and 3500rpms steady throttle).

The car has a programmable EFI system, fairly stock motor and a high flow catalytic converter in the system. Recent plugs and plug wires.

To reduce NO emissions, do I want to lean the idle out to stoich and advance the timing?
Are there any additives members have had success with in the past?
Best,
John

 

My car, with the Andial kit, simply can not pass state of Texas emissions. The car's prior owner in Va. could not pass their either. I now just take it to my independent tech here in Houston and give him the car for a week or two to get it through.

You can play around with the idle and timing as well. I played around with a bunch of things.