stephen p luce
Newbie
92 K1500 5.7 TBI failed calif smog test due to high NOX measured 716 at 15mph and 572 at 25mph. All other specs well inside the fail window. Any ideas as where to start? EGR leaking?
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^^^This, worst case scenario, you may have to pull the intake manifold to get the passages cleaned out.Since there arent any check engine lights you can try taking it off and cleaning the orfices and hopefully its just a clogged artery.