Two years ago my dx failed smog and I put a new oxygen sensor and cat on pass with acceptable levels. The quick fix got me through but my time has come again. These readings are from the dyno style smog check. Here is where she failed @15mph Co2 14.5 O2 0.00 HC 116 CO 1.11 NO 1000 She passed here. @25mph Co2 14.9 O2 0.00 HC 63.0 CO 0.25 NO 438 The car is due for an oil change with 3100 on the current oil. Timing is 18 degrees. The plugs and wires have a few miles on them and I am going to change them. What other culprits should I be looking at? Thank you for any help. -Brian G