I did some research into your purchase history and back-tracked it to the ink batches, etc to just verify the history. Sorry for the delay, I've been teaching all week.
The problem is most likely a damper that needs replacing. These generally need replacing every 1 1/2 to 2 years on this printer. The one thing I suggest is to never print with nozzles out on this particular printer (x890) because this could burn out a nozzle.
Because the nozzles eventually always come back, the cleaning assembly is not a problem. That said, this will be the next part to go on this printer and I always advise people to replace the "ink selector assembly dampers" as well as the cleaning assembly (vacuum, flush pad, wiper blade, etc) at the same time.
Both items can be purchased from compassmicro.com and replacement is an afternoon or so with the printer, a long #1 magnetized screw driver, and a long #2 magnetized screw drier.