I have a 94 honda civic lx that keeps failing the ohio e-check for NO. Does anyone have a suggestion on what i can do to get it to pass. I have already changed the oxygen sensor and it didn't help any, in fact it got worse. Any suggestions would be helpfull Thanks.

 

welcome to the forum. Have you changed the oil and filters, air filters, or had the engine tuned up before your e-check. Also is the catalitic in good condition.