87_notchfox

so i came up on a really good deal on a pretty well maintained 04 f150 lariat with 195k when i got it. it had codes for misfires and knock sensor. but after i took it home changed the fuel filter and took all the plugs out which were all lose and almost new i put everything back together and the truck was running fine. then the p0174 code came around. i changed the MAF, plugs, COP, seafoam'd it, fuel system cleaners, pulled the intake off which was missing 2 bolts, new front o2 sensor, replaced some of the vac lines i am at a loss. i dont hear a exhaust leak and the manifold doesnt show signs of leaks. i really dont know what else to do. i need to smog it and thats the only thing holding me back. has anyone experienced this and fixed it that can point other things i might have missed out on. also fuel pump and PSI is fine. i get about 75psi at at koeo. but i have noticed that when i start it up it seems to hesitate like its either out of timing or doesnt have enough fuel psi. but after maybe 10 sec it runs fine.