With these new 3v 5.4 i was noticing how they run rough and noisy at low rpms, such as 800rpm. It really . Had two of these trucks now. Had to get rid of the first one because it would drop the left side of the engine when given a little gas because a piece of slag would block off an oil gallery due to lack of oil pressure to push it through. Now with the new truck you can hear the same slapping sound which reminds me of lack or oil pressure to effectively operate these hydraulic phasers. You rev the motor past the 1200rpm (after the oil pressure gets up) and let the rpms drop and there is no noise or vibration. Seems to me like ford didn't put in a large enough pump to operate these phasers. My cousin's work truck also a phaser problem too due to low oil pressure. My buddy who is a mechanic at Ford commented on this the other day which made me decide to put it on this forum and see what everyone thinks.

Would putting in more oil than required help it out or maybe adding some sort of auxiliary pump help things. Motor run fine it just seems slightly weird.

 

2 trucks with the same problem? something dont sound right to me. what kind of oil do you use? and filter? and how often does the oil get changed? sometimes putting more oil than the engine is meant for can do more damage than having low oil. if it gets overfilled(over the max line) then it'll get air bubbles, and wont do its job efficiently, and it'll cause alot more wear, etc.

 

This sounds like the exact same problem I'm having except mine is a 2v.
2002 F250 5.4L

 

5W20 mobile one. Both were 08 trucks. Both with similar problems. Apparently the 08 motors didn't get washed well by the sounds of it. Before that first truck i had the dealership already had 3 trucks imploded from sand in the engine from the casting process according to my friend. One had 500kms on it. Said the vibration is a common problem among the trucks. Mind you mine also has a drivetrain vibration issue above 120 kms/hr as well. As much as these issues are disheartening me to ford i could never go for a torque lacking truck of other manufacturers such as GM's 5.3(gutless).

Get the oil changed every 5000kms. Ford filters. Always got ford to do the oil changes.
Vibrations were there from the get go. First truck was rough at 70km/hr or 1100rpm, new truck is more 800 rpm.

I was searching the forums and came upon a problem with the doors that somebody else had with their 08 about a rattle near the lock. Both my window regulators are loose and make metal on metal rattles at the right conditions as in turning or temperature. If you have a rattle its probably because their loose. Under normal driving conditions its just a rattle, not metal to metal. I had the drivers side tightened, no more rattle but they didn't do the passenger side and there is a rattle still so if anyone reads about this pass it along. I got 3 buddies with 5.4 f150s from 04 to 07 that don't have this problem which leads me to think its an 08 issue.

 

and never put more oil than the mechanics put in. Its all felt through the pedal but on my friends truck you feel nothing. Maybe they changed something. Oh ya an my cousins work truck is an 08 as well. I also forgot to mention that my fathers friend just had his Harley Davidson's tranny completely destroy itself at 25 000kms. Nothing left according to the dealership.

Funny coincidence isn't it.

 

First off get rid of the mobile one and go to 5/20 syn blend MC oil and see what happens, how do u know u have low oil pressure have u put on a mech. guage factory guages are nothing more that an idiot lite with a needle, and I believe the cam phaser issue was fixed in early to mid 07?????

 

I'm quite aware of ford cheapness in the area of functional gauges. Just making assumptions in the way of oil pressure here if you were reading what I wrote you might pick up on that. Secondly how would changing to 5/20 MC oil change anything? Its the same viscosity. Not only that but the truck did it before I changed to mobile.

 

mobil 1 is having issues passing certain tests for ohc engines. they are causing more wear. the 4.6 and 5.4 are ohc engines. its only the regular version though not the extended performance version. and its not an oil pressure issue for the phasers. the oil pressure only adjust the tension on the timing chain for the "VCT", the issue with the older cam phasers was a pin wearing out and causing a noise. how many miles on the motor? what is the oil level? and how many quarts did you get the dealer to put in it? so you rev it and the slap noise clears up?

 

Making assumptions on oil pressure tells u nothing, mobil one is full syn. which ford does not recommend and if u do a little research on these forums u will find mobil one has failed a number of different oil tests and I doubt seriously that there is any junk left in the engine blocks after machining, most of what u describe makes no sense!!