I’ve got an 09 f150 5.4 and about 6 months ago I replaced the cam phasers, did a complete timing job, replaced oil pump, coils and plugs, vct solenoids, cam shaft position sensors and the crank sensor. That fixed the problem for maybe 4 months then it’s right back to a rough idle, slow accel. Stalling, and at times it’s almost loping and fuel mileage has gone to hell. All cylinders except 7 are random misfiring and I’m getting these codes: P0012, P0022, P0150, P0300, P0346,P0341, P1464. I’d really appreciate any advice on this one.

 

What brand of timing chain kit did you use?

 

All Motorcraft parts should be used except for the oil pump, where you use a Melling.

 

There's no easy way to say this, but I think one of your new cam phasers may have just hit the "warranty" button. Your one saving grace may be the oil itself. What oil you put in it during your last oil change is irrelevant for this test, so don't go there. I know the purists are going to knock me for this one; but this is for diagnostic purposes only. Buy a quart bottle of Lucas Standard Oil Stabilizer. Do NOT get the "Synthetic" one; it's not gooey enough. Remember this is for DIAGNOSTIC PURPOSES; you'll be draining it out as soon as you get your answer. Pour in the entire quart bottle into a COLD engine. Yes, you want it overfilled for this test. No, you won't hurt it; if it's "hurt" it's already hurt and you won't make it worse by having it overfilled. Allow it to fully mix with the oil before you start the engine, so give it like 5 minutes or so. Start the engine. If it will do it, allow it to warm up and go into closed loop. If it improves it enough to drive it, drive it and see what happens. (don't hot-dog it, by the way, you're doing diagnostics, full throttle test comes later)

If it "fixes" it completely (which is unlikely) then your oil is too thin, and you need to go up a level in viscosity. Most techs that do a phaser job usually recommend running 5w30 instead of the OEM's 5w20. It may interest you in knowing that synthetic oils don't have the "clinging" or "sheeting" action that conventional oils are known for, and looser engines can sometimes do better using conventional oil. My XJ8 developed a cold rattle after running Royal Purple (which I now know is junk oil) for a month. The Lucas add-in filled the gaps, and the rattle went away. I'm now using Valvoline Conventional and my XJ8's engine has never run better. Just know that synthetic oil is not ALWAYS better for your application... The Ford 3-Valve is very sensitive to proper oil pressure. You never know, you might be a simple oil change away from that thing running correctly again. It's possible, yes; likely, mmm, maybe.

If it merely "improves it to a degree" (which is more likely), then it is likely something in that timing area has failed. I have seen the pressurized chain tensioners crack and leak like a seive due to an overtightened bolt, causing oil pressure in the head to be all over the place. But then again, I've also seen Dorkman Cam Phasers explode right after a timing job; which is the reason most techs that have done that job scream up and down about the importance of using ONLY 4th design genuine Motorcraft ones.

If it doesn't improve it at all, I would remove the valve covers to see if any of your cam followers has jumped out and ended up in the oil drainback valley and allowed any of the lifters to jump out of their bores and leave a massive opening for excess oil pressure to go.

Good luck.