Hello all, I have an 83 toyota 1.5 l 3a engine in a little tercel. Went for smog test and failed, tech said readings were in range and then went bad. Failed readings are 2500 rpm, hc 319 ppm; co, 0.00; co2, 9.7 ; o2 6.8 ; idle hc, 295; co, 2.75; co2 10.6; 02 3... Login to read more.