Ok so for over two years my truck has had a rattle at start up but would always go away after a few seconds. I was told by my dealership I needed cam phasers to correct the issue but I never had the work done because they wanted $2800 to fix it.
Well this last week my check engine light came on and the truck started idling rough. I checked the codes and I had p0012, p0021,p00345, p00303. After some research I decided to change the vct selenoids which was surprisingly easy. Well I cleared the codes took the truck for a test drive and still had 3 codes p0012,p0021,p00303. At this point I changed the spark plug on cylinder 3 and this eliminated the p00303. The truck does seem to idle a little better but still is not right. I still have codes p0012,p0021.
At this point I'm thinking the timing chain jumped or something else is throwing the timing off. So aim going back to the dealership to see about getting the phasers done. My question is I want to make sure they change everything that needs to be fixed why they are in there. I only want to pay for this once. Here is what I have come up with so far.
Some people recommend replacing or at least inspecting the housing that the VCT solenoids install into. Apparently there's a small orifice in there that can be blocked? I don't know a lot about that except that I read about it here or elsewhere after putting mine back together. I didn't inspect or replace them, and all is fine.
That should stop the "diesel sound". While you're in there, it's a good opportunity to change the lash adjusters and cam followers in case there is some slop in them. That could be a source of noise, but isn't directly related to the cam phaser diesel noise. It's a little extra labor because the camshafts have to be at least loosened and maybe removed to get the lash adjusters out. You might just inspect those to see if they're ok and replace if you see wear.
Also, you should use only motorcraft oil filters after you fix it.
Thank you for the reply and suggestions. I would like to add that my truck does NOT have the diesel sound or knock/tick but does have a brief rattle at start up. I think the timing chain must have jumped off track causing the codes p0012 and p0021. Does this sound right? I changed my spark plugs today and and the truck idles good now but I still have the codes/cel.