This is for BIGJOE...
Go to autozone or the equivalent. Get them to read the code. You will know then and there if it is a coil.
It definitely sounds like a misfire and a bad coil is a possible culprit. I would get the code read for free and then go from there. If it is the coil then yea the car will run fine after. You could also do a self diagnose by removing all the plastic shit on top of the engine. Disconnect one coil at a time and see if the way that the car idles changes, does it run rougher or the same.... If you unplug a coil and the idle gets worse, then you have unplugged a good coil, so plug it back in. If the idle does not change at all, then the coil you unplugged was already dead and needs to be replaced.
2006 330i - Jet Black - 19" E46 M3 wheels - HR Sport - 206,000 Miles...