The Nissan Path

After I had to swap out the distributor and reset the ignition timing, it's been running rich and idling higher. When I took it in to a shop, they said they adjusted the timing, replaced a fouled plug in cylinder 5, but the cylinder was still misfiring. The engine issues are still there, but it still runs like a champ. Is there anything I can test to rule out some possible causes?

Check for spark to #5 spark plug. Unplug the fuel injector harness connector and install a noid light to make sure the #5 fuel injector is firing. Component test the fuel injector by check the resistance. Compression test. Cylinder leakdown test.