i have a 92 trans am that never passes smog everytime its the Nox or something like that. i have chasnged the cat twice and the egr valve 5 times cuz they give me the wrong one that was last time now now its high nox again very lil but this wont pass this year again. any help would be great

 

you could try one of the fuel additives that is supposed to get you passed on emissions. i know its not a fix but it would get you inspected and on the road. CRC part number is 05063. should be around $10. also, theres a decent thread about this with some other ideas as well right here on TGO.

https://www.thirdgen.org/forums/afte...teed-pass.html

good luck.