'94 GA Emissions

I've always had good luck with automotive forums, so I thought I would post this question on the Grand Am forum.

I hava '94 GA, with a 2.4 liter engine, with 49k miles. It has been maintained well, and just had a new ingnition coils installed.

It failed NOx during it's inspection. The standard is 1045, but the car read 1573.

It passed HC and CO%.

The check engine light is NOT on. Is there something that I check or change before I take it a mechanic, such as an Oxgyen sensor?

Any help is appriciated.

The egr valve could be going bad and will effect NO2. Also you didn't say how many miles you have on the car but it is possible that the cat is going bad. A lazy O2 sensor could also cause too much fuel to go into the engine and decrease the cat efficiency. Start with the egr valve to make sure it is working properly.

The 2.3 quad used 92-95 did not have an egr valve. I'd start with the o2 sensor, it's around $25 and very easy to change as it's right on top. If that doesn't cure it, change the plugs and your fuel filter and make sure your throttle body is clean.

Thanks for the replies... The Car has 49,000 miles, my mother in law got it new, and now my daughter drives it. A mechanic friend said EGR also, but if doesn't have one, then it can't be that. Also, there is no visible smoke, even on start up.

Temp gauge only goes up a 1/4 of the way, would running too cool cause this problem also?

I will start with the o2 sensor and new plugs....

I agree with the Above.. The O2 could be the culprit..

Let us know what you find after the plugs and the O2:)