1999 Jeep Grand Cherokee start stall

Well at first it ran fine except after about 2 minutes running it would start to spit and sputter and id just throw it into neutral rev it up a few times let it idle for 30 seconds as engine would not kill then it would run fine until the next time you started it and then it wouldn't do it every time then 1 day it got worse spittin back threw the throttle body when you stepped on gas to hard but made it home next day did a key on key off on again and got code for 1/1 upstream 02 senser and P1491 fan relay wich It has a mechanical fan so didn't think nothing of it so I bought new 02 senser replaced it checked fuses relays at power distribution center and notice som e wires coming out from it that run to a relay with 2 green wires hooked to it 1 that looks like connecter broke off relay the other is fasted to ground bolt on right fenderwell behind power distribution center and know the damn thing will just start die and run only for a few seconds so I did key on key off key on deal and no codes except fan relay so I notice needs new valve cover gasket I replace that replace PCV IAC Valve Map senser fuel pressure regulater and know it justs starts stalls and when it does start for few seconds the oil pressure guage blasts clear over to 80 psi any help would be greatly appreciated