When I went to register my car in Delaware (it's a 1982 240 model) it had to pass a 2 speed idle test, and it failed the Hydrocarbon test at the high-speed idle. The reading was 326, and the limit was 220. It passed the low-speed idle, as well as the other parts of the emissions test (the readings for all the other parts of the test were far from failing.)

I'm going to get it looked at, but I was wondering if anyone could give me some pointers - what might be causing this? I just had a new catalytic converter installed a few months ago.