This report presents and summarizes exhaust emissions test data and other related information obtained in the testing and inspection of 116 in-use passenger cars. The test fleet consisted of 1979-1980 automobiles equipped with three-way catalyst emission control systems. The test vehicles were obtained randomly from private owners in the Los Angeles and Orange County areas. The testing was completed August 1980. Each vehicle was tested in as-received condition and given an underhood emissions control component inspection. The test sequence consisted of the 1975 Federal Test Procedure, a Highway Fuel Economy test, a Bagged Idle test, a 50 mph Cruise test, a Four-Speed Idle test and a Loaded Two-Mode test. Twenty-five of the 116 vehicles received an evaporative emissions test using the SHED technique. Nineteen of the 116 vehicles received restorative maintenance repairs and additional testing. Twenty-three of the 116 vehicles were specially selected Cadillacs with four of these undergoing selective malperformance testing.