That thing will pass smog while it misfires horribly. As long as the check engine light isnt on it will pass no matter what.
Re did the top end awhile back and never been quite right.
Smog problems usally are: O2 censor, mass air flow censor, cat if its been running rich for a long time (common to correct low idle issues).
Bottom line its cheap and easy to work on. Diagnosis for me is the hard part.
Your smog tech is critical, I perfer the alcoholic wheeler type.
Edited by Ambush, 02 April 2019 - 01:31 PM.