As Fleetwin noted, the Phasers can get noisy but they are fairly easy to change if you are mechanically inclined.There have been several TSB's which change the frequency of maintenance and spark plug changes have been reduced to 60K and there are several TSB's on the procedures for them. A seperate TSB concerns changing oil from 5W-20 to 5W-30 and to ensure you use an oil filter (Motorcraft recommended) which has the silicon anti-siphon valve. The other TSB with which i am familiar with is to grease the slip yoke on the 2 piece drive line and to ensure that the rear end oil is 75W-120 with additive in it. I currently have 210k on my 5.4 and it runs fantastic. Also have a tuner on it with a cold air intake, dual exhaust, and several other mods. There are 2 transmissions that come with this engine, The light duty will not take a lot of abuse, the heavy duty is a work horse. I average about 15.5 mpg in heavy interstate traffic with an average speed of 30-40 mph, cruising on the interstate it will turn 18-19 mpg at 70 mph. Towing is fantastic, rated at 10k and doesnt know you have a load most of the time. Shifts up into OD and never shifts out running empty, normally doesnt shift below 3rd at 70 when towing. I have replaced 1 coil pack at 156k but no ignition issues. I have changed the waterpump 3 times. I change oil every 4-5k using Penn 5W-3p Semi Synthetic. IF the truck has been maintained regularly, i would not hesitate to buy it.
