allthatisman

My buddy has a 92 sc400 with 152k... fairly good condition, runs excellent. He went to smog it and get it registered here(it's from Florida) and it passed everything else with acceptable margins, but showed a really high NOX reading. Wouldn't a bad EGR cause the car to stall out and run, not well? Any thoughts? Like I said, the car runs and idles like a brand new car... maybe it needs some sort of additive?