I have a 99 3.5 v6 jackaroo had the heads done up put back together and we found we had the timing slightly out fuel pressure was great, fixed the timing problem and it runs, BUT it started running on 3 cylinders (left hand bank when standing infront of the car) put a code scanner on it and it keeps showing code 33 fuel presser regulator open circuit and there is very little pressure in the rail, have tried swapping fuel lines and no diference, have attached a vacume guage to the port and it has plenty of vac unsure if it is the pump or the reg and as they are expensive I was wondering if anyone had any similar problems was running fne before heads came off (it overheated)