P0300, P0302, P0304, P0306, Engine running rough with little power

[X5Cat]

Help, please! This 2009 X5 3.0 started running rough last weekend as my wife was on her way to Baton Rouge. Pulled codes when she returned and got the P0300 (general misfire), P0302 (#2 cylinder misfire), P0304 (#4 cylinder misfire), P0306 (#6 cylinder misfire). Also had a stored P0301 (#1 cylinder misfire), but it did not reoccur after I cleared all the codes and rescanned -- the even numbered cylinder codes and the P0300 did all reoccur. The vehicle just has no power, and she really can't drive it without getting a lot of ugly gestures in traffic.

I should mention that I also have a P0442 (small evap system leak) which has been there for several months and will not go away, but has not seemed to affect performance. I replaced the fuel pump months ago in response to that code and other symptoms (related posts elsewhere on this site). That cured the observable symptoms but the code will not clear out. I would of course like to fix that but don't think it is related to my big problem now of the even cylinders misfiring, so I don't want to dwell on that one for now.

I'm sure plugs, coils, etc., are normal suspects, but with it all coming on very suddenly, I don't see where it is likely to be something related to individual cylinders occurring all at once. Ideas would be appreciated!