I just bought my truck about a month ago and so far have loved it other than a few issues i have had with it. It is a 2008 F250 With the 6.4 and a zf6 transmission. A week ago while doing about 300 miles of freeway driving and the truck started to shudder over about 2K RPM, I thought it was plugged fuel filters, so 3 days ago i replaced the Fuel filters, and everything seemed fine, but it was only getting up to 30 PSI of boost. Then this morning while i was driving into work i noticed it wouldn't go above 10 PSI ad that was it, other than one pull when i was getting off the freeway were it went up to 20 lbs of boost. What kind of issues could be causing this? i hooked it up to my diagnostic computer at work and it isn't reading any codes.