Originally Posted by sonicblue2003

Well, I fully agree that the PCV elbow can cause a "random misfire" P300 code. I just bought a 99 SD SC 4x4 V10 and it ran like a bag O crap. Decided to throw a set of plugs and known good coils in it and noticed a crack in that PCV hose.
When I removed it , it had two 1" long cracks in it.. Being sunday and all... I carefully cleaned and taped the hose.Monday I will get a new one from the dealer.
Now the truck runs like a million bucks!!!
BTW I just bought this truck for $2500 and everything works.. ESOF 4x4 and all.