3 months ago our excursion with 163,000 miles died. Took it in to a repair shop and had low pressure from the hpop. replaced the hpop. Pressure back to 3000+ psi. Engine would start right up. Noticed when the engine is hot that low oil pressure light came on at idle. Called the shop. He said probably a oil pressure switch. Drove the 250 miles home with no issues except for the low pressure light coming on at idle. Replaced the switch myself, but light still on. was test driving and while pulling a hill, blew oil from the exhaust. Found turbo seals to be bad. Replaced the turbo. Still the low oil pressure light is on at idle. Took to local Ford dealership. Manually tested the oil pressure and determined that the lpop was bad. Replaced lpop. Still have low oil pressure. Manual guage is reading 10 psi. Through all this the truck starts right up, so I'm not sure its the hpop. Have had several conversations with the mechanic that put in the hpop, and he assures me it was done right.(He is a friend of my parents) I am now 6k into this problem and everyone seems to be guessing. Anyone with help will be greatly appreciated.