Engine Vibration and Misfire: Possible Causes?

[mamba]

Hello all. Tonight I started my buddy's Ti after doing some work to it. We replaced the following:

Spark plugs (Bosch super, pre-gapped)
Wires
Coilpack
Cam position sensor
Valve cover gasket
Oil pan gasket
Water pump
Thermostat
Radiator
Radiator hoses
Air intake boot
Engine mounts
Suspension
Brakes

The car has been sitting for about 3 weeks. It started right up and the idle seems steady, but I am hearing what I am pretty sure is some misfire action at the tail pipe and the engine seems to have a little bit of excessive vibration. I ran the engine for about half an hour while waiting for the fan to come on (flushing coolant system). I had a look around and read several posts about misfire issues and rough running issues, but most of them don't have any resolution or follow up posts that tell how the problem was fixed. At the moment there is no check engine light.

While it was running, I went over the bay several times checking for loose connections or something that might have not been plugged in and didn't find anything. Any ideas about what I should check first? Second? Third?


Thanks!