ford 5.4 3 valve oil pump
I have been through all the throubleshooting on this engine and let me tell you this. If you are having noise from the phasers, broken timing chain guides, sounds like a diesel, sounds like powersteering pump whine, oil pressure gauge goes to zero intermittently. THE OIL PUMP IS THE CULPRIT!! The oil pressure gauge is a dummy light in disguise. It will read normal untill it gets down to 5 psi or so.these engines maintain upwards of 70 psi at highway speeds and at least 25 psi at low idle. Thats a lot to ask from a pump long term. My suggestion would be to watch everything on YouTube about this engine. Inspect the phasers, replace the timing chain set, replace the oil pump. While the front cover is off flush the oil pan and pickup tube with diesel and let the sludge drain from the oil plug. Reassemble and be done with it.