Can't figure it out

[hex0rz]

:think:Okay, so ever since I've had the whole shpiel with the truck last time running funny, it seems it still will throw a couple codes.Going in the mountains this weekend, so I decided I would run a code reader on it see if it is still running good. Well, turns out it threw a P0234 code 2x. Checked the ECM and PCM as well. Dunno if these trucks allow it or not, but the reader said unable to communicate with the ECM.The PCM said there was companion code set.Now, I dunno if anything serious is occuring or not, but I would sure like to figure it out. I definitely would hate the idea of being broke down in the MIDDLE OF NOWHERE!I have suffered from lower fuel mileage rating and since the first occurance of this problem about a month and a half or so ago, the exhuast has been smokier. Before this occured, my exhaust was barely ever smokey. No on a good accel, it will smoke good.As far as I can think of, with all the symptoms and codes being set, by bet is the turbo. Especially since seeing the inside "damage" that was done with the k&n filter that was in there.I really really hope it is not an IP or something!Could I have a dirty or bad MAP sensor?I suppose that would not explain the P0234 though...