car is a gross polluter on 1990 Chevrolet Corvette

failed at co and hydrocarbon, have no known codes on the computer

Asked by for the 1990 Chevrolet Corvette
you need to have the engine checked out. plugs, wires, cap,rotor, air filter, o2 sensor, map sensor, cat and compression test. all these things need to be checked for a fialure.

have installed new plug wires, distribitor cap, rotor, checked the plugs ,seemed ok.. the cat conv. were tested (pass)at smog station.
o3 sensor switching fast enough?? what are the cross counts?? how did they test the cat operation??