I replaced all of the timing components to include the cam phasers along with the VVT solenoids, boots FordRacing HF Oil Pump, water pump, thermostat, spark plugs, COPs, alternator, battery, o2 sensors, both Cats and a bunch of suspension work over the past 6.5 years. Finally after replacing everything my truck is driving as it should have been all along. I did the timing and oil pump job in October and have since driven it cross country, gone into the mountains and snow with 4x4 and put roughly 5500 miles on it with absolutely zero issues with leaks or other mechanical problems. I achieved 18.10mpg while driving over 500 miles on a single tank on cruise control @ 65mph having only stepped on the brakes a time or two on a long straight flat road. It drives like a mustang now and I'm probably due a speeding ticket with all the fun I've been having now that it performs so well.
I have not given in and purchased aftermarket parts for any of the engine except for new dorman valve covers (because a few of the plastic like anchors the COPs are fastened to broke) and whatever brand CATs i got. From all the posts I have read I wouldn't risk putting anything but the OEM into the engine. I have 248K Miles on my truck and it's not going to die anytime soon.
