I have a 08 f150 5.4 bought it non running scoped all the cylinders no signs of any valve contact retimed it chains guides tensioners phasers and vvts runs great until exactly 190 then it idles rough but still runs great if you raise the rpm slightly no matter how hard you are on it itll run great until until 189.9 but as soon as it hits exactly 190 first time you touch the throttle at all it permanently idles rough until you shut it off and get it under 190 but if you never touch the throttle itll idle perfect for unlimited time st one point it idles great for 4 hours reached 205 at one point still ran perfect I gently tapped the throttle barely even made the rpm needle move and it started chugging the dealer says its the oil pressure causing it but it seems way too precise at exactly 190 I feel like its a tuning issue im bringing it home in the next few days oil pressure is only 17psi but if thats the problem why can't I make it **** up at even 189

Edit: Changed the oil pump it now chugs at 26 psi when it used to run great under 20 adding 10psi of oil pressure had literaly absolutely 0 affect I guess atleast it has more oil but otherwise complete waste of time and money

 

You need to figure out that 17 PSI issue. Why? Phasers need about 25 PSI to operate properly and they do kick in when you tap the gas pedal.

Whether it’s a clogged oil pump pickup or other internal wear, figure that out.

That makes your temperature findings irrelevant at this point.

 

changed the oil pump yesterday it now idles hot just under 30 lowest point was 26psi and it made absolutely no difference at all not even a little bit

 

Try unplugging vct solenoids and see what happens when warms up and raise idle ....it’s a long shot if you replaced them and they are clean won’t make a difference. Usually dirty screens or varnish in those solenoids can cause problems even engine to stall.

 

first thing I tried should've said that but it makes no difference at all except less hp no affect on rough idle I did discover it was charging at 13v replaced the alternator which did make it better itd now realistically drivable but still misses hard at idle atleast that's what it sounds like