My 98 Trooper (150K plus miles)failed smog. High Nox.


I''''ve replaced the EGR since the original is black and uncleanable and installed a new one.


NOERROR codes seen by thescanner. Ran the truck over the weekend for a few hours to clear out any codes. Truck ran fine and still strong, no issues just failing smog...Retested it, same problem...any ideas what the fix is?


1. Tune up is due this weekend, change plugs, oil change, clean MAF sensor, change air filter...


2. Clean out throttle body with carb cleaner..maybe?


3. Not surewhat else I missed....


Any help is very much appreciated.


Thank You.


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Edited by: gnr_70