i have a 2004(late model) ford f250...i week ago i had to put an injector in for a code p0284.while i was all energetic and since this truck is new to me and i have no history on it i decided to do an egr delete, replace the oil cooler,all fluids and filters...big chunck of money.always before when i started the truck i could watch the oil psi gauge and as soon as it got half way it would start...now when i start it ,it starts then my oil psi raises off zero to half way..my concern is do i have air in the oiling system????it sounds horrible when it starts like air in hydraulics for about the first minute then it quiets down and sounds smooth

 

It's quite possible. They say to bleed air out of the high pressure oil system you need to hold it at 3k rpm's for 3 minutes. Or just go drive the snot out of it.