When I picked it up it ran... somehow worse than before. The engine idled very roughly and shook the car like it was about to fall to pieces. This was... disconcerting, since I had just paid for a diagnostic to look into just such driveability issues. At length I came to the conclusion that I should replace the spark plugs and see what that did for the idle. In the process of putting in 6 new plugs of my controversial preferred brand, I broke one of the ignition wires. That meant a new wireset had to go on too. With the new ignition components, idling felt significantly better, and the engine is slightly less apt to stall now. That, plus an 18" tailpipe extension, and I was ready for the Cone of Shame (the state emissions test).
The car got some confused looks in the service lane, and during the under-hood inspection I heard a "what's that?" at least once, referring to something in the engine.
Then the Cone of Shame went on the tailpipe, and Shame it was:
Of course, the Shame could be worse. You see that everything passes except hydrocarbons, which failed spectacularly. However, the guy I talked to there all but told me that this is probably due to old gasoline in the tank. It happens a lot with cars that have been sitting a long time. The gas gets old and doesn't want to burn, leaving unburned hydrocarbons in the exhaust. So as soon as I can get the right gubmint permit, I'll be running it around town, trying to burn off the old gas for a while, then trying the test again with fresh gas.