Thanks for all the good advice to date. I was hoping it would be the least costly of all the items I listed!! To your response David, I don't have specific readings but for the NOX readings, the applicable standard is 3.0 grams/mile and the Delorean is putting out 5.4 grams/mile. The other readings were: Hydrocarbons (HC) .10 g/m (standard is 2.00 g/m); Carbon Monoxide (CO) 1.3 g/m (standard is 30.0 g/m) The car was fully warmed up for the test. The car runs fine -- perhaps a bit hesitation when cold but nothing really major to be concerned about. While the NOX reading is not excessively high, if all that is required is a tweak of the air /fuel mixture, that makes me happy. Is this something I should attempt or just take it to the professionals? Mark D. 16728 ------------------------------------------------------------------------ To address comments privately to the moderating team, please address moderator@xxxx