Okay so i went to smog my car today. i have carb legal dc headers, stock cats, stock y pipe, 3" y-back exhaust, jwt pop charger and aftermarket Z and also a skunk2 plenum spacer. i take it in for a smog, and now im told my NOX levels are too high (meaning im running too lean). So, i go home, put my stock intake back on, remove the plenum, and go back for a retest and now my NOX levels got worse?? hows that possible? so what are my possibilities for me running too lean? obviously im in need of a tune. but if i were to say order the cobb accessport and flash on a new map, will that even out my levels enough to pass it? the smog guy said it could be my o2 sensors going bad? Any feed back would be great guys, thanks!

 

did u reset your ecu after putting back some stock parts?

 

i didnt unplug the battery or anything but it got a good 25-30 miles on it before it was re-tested. would a tune effect it enough to fix my a/f to pass smog? i've been needing another reason for a tune.. hahaha

 

well i would recommend getting a tune regardless but wouldn't hurt to try unplugging the battery. if all else fails get the tune.

 

Can also mean carbon build-up causing high head/exhaust temps like a lean tune would do too. High head/exhaust temps = high NOx.

I'd clean-up your c/c's and valves first with something like this:
http://shop.oreillyauto.com/productd...goryCode=3233+
or
http://shop.oreillyauto.com/ProductD...goryCode=3233+
or similar. Plus do a ECU reset then try again.

Bad EGR (if equiped) will result in high NOx.

 

What part of nor cal are you in? I know a gas station in hayward that will pass you no matter what

 

ah, im in Sacramento. if it comes down to it though... haha