I recently failed my state's inspection due to high emissions; specifically, nox. the state's limit is 2.5 grams per hour; my car emits 3.07 grams per hour. What the state cites as common reasons for failure are the catalytic converter. With a replacement cost ranging from $700 -$900 US for the part alone, I am seeking alternatives. Someone recommended a fuel treatment called "Guaranteed to Pass Emissions testing" that is added to fuel. After using the treated tank of gas, return to the testing station for a retest, accordingly the manufacturer claims users will pass the emissions test.

It makes no sense to invest so much money in a car thirteen years old. the car, like any volvo, seems to have much life left in it, i don't want to replace it due to a marginal level of a pollutant. Certainly more nox would be released during the manufacturing of a new vehicle.

Any thoughts?