Need help !! I just change out oil and both fuel filter last week, and I notice my 2006 ford f350 6.0 had been running a bit rough during idle and have some knocking sound, the weird part is sometime it went pretty bad and sometime you can hardly notice it. Just get to put the code today and it show p0281, p0284 and p0528 3 codes. can anyone give some advice on what might went wrong and I can do to fix it or should I actually go to dealer to get it fully troubleshoot the whole thing?