Had my car in for emission test a failed High NOx on driving test 1147 ppm. Replace muffler, fuel filter, changed oil, added fuel conditioner, new spark plugs, tested EGR valve with vacuum gauge, and no codes on dash. 2nd test results 650 ppm failed. What should I check next. Thanks
have the same problem?
Friday, August 8th, 2008 AT 11:50 AM