Hello-- I've got a 2005 Chevy 3500 dually chassis cab 4x4 auto 6.0L.
Last week it started running very rough. Threw codes p0101, p0134, p0171, and p0300. After reading about these notorious intake gasket problems, I just went ahead and replaced the gaskets. The old ones "looked okay", but I just shrugged it off and went along with the $75 replacement Felpro Premium gaskets. 1 week later, the same thing is happening and it may even be just a little worse than before. I checked the torque of the gaskets and it's spot on. However the fuel pressure is in the 45's while idling.. Spikes up to about 55 WOT, and that is about all of the diagnostic info I have.
Any ideas? Thanks for looking.
--Ken