Failed inspection

in the last 2 weeks my car, a 1994 honda accord LX, had failed the NY state emissions inspection. the first time around the mechanic told me that the car needed a tune up. i did that. the O2 sensor has been changed. there was a leak in the valve cover, i changed that before i did the tune up. then i took it again and it failed the inspection again. any ideas wat the problem could be? i know the O2 sensor is not part of a tune up. lol. its just that it was the first check engine light i had after i bought the car and the mechanic said that the O2 sensor is one reason y the NOx reading was a lil high. he said that it wasnt too high but enough to fail the inspection.

High NOx usually means the EGR system is not working or the ports on the intake manifold are plugged. Honda has tests to check the EGR valve and also to determine if the ports are clogged. I gather you checked the ECU and there are no stored codes. Did they give you a print-out of the test? It helps to have all the varius tested numbers and the max to pass to help evaluate the problem.

thanks. how can i check the EGR? cuz the mechanic also mentioned wat u said to me. both the EGR and the intake.

http://www.automotiveforums.com/vbulletin/showthread.php?t=943632

We just went through all this a few days ago...look here, probably find your answers...

For starters, check the following thread

http://www.automotiveforums.com/vbulletin/showthread.php?t=943632