So my car failed emissions, where AFAIK it passed with flying colors the last two times. It read 200PPM (hydrocarbons) on the 2500 RPM check, 175 on the idle check.
Things we've already tried: Checking the dwell & adjusting the mixture, making sure the O2 sensor wasn't loose, checking for vacuum leaks
Things we're going to try: replacing the spark plug wires
Is there anything else obvious that I'm missing? I feel like I must have screwed something up when I was working on it last fall. I did trip over the mixture unit while it was sitting on the floor, is it possible that I broke something inside it?
The engine was overhauled in winter 2016 at DMCCA and it has a DPI exhaust (new when I bought the car in summer 2016.