94 K on a 2001 Expedition AWD with the off road package. The only issue we have had is the famous plastic intake manifold cracked at 87K. The dealer replaced the intake, and did the 100K tune-up since I was paying the labor to remove all of the parts anyway.

We used a Dorman aftermarket intake, and so far so good. The mechanic said that the Dorman unit uses an O-ring to seal to the heads, and that is different than stock. He was not sure how it will hold up, but said that it went together nicely.

She runs great, always has. We have not had issues with the spark plugs, and the mechanic told me that a lot of it has to do with using the proper torque when installing them. Time will tell...

For service, I do that part myself using Castrol GTX 5w20 and Motorcraft filters. The oil gets changed at 3K without fail. No leaks, no smoke, and the oil still looks clean and full at the 3K mark.

My son has a 99 F250 4x4. His 5.4 spun a main bearing at 140K. He was not running the correct oil in it. He was using 20w50 and changing it infrequently. He had a remanufactured Ford engine installed and now has 70K on that one, with 210K on the truck. He learned his lesson about the 5w20 oil and changing it and the filter on a regular basis.

My sister has an 02 F150 Supercrew 2wd. They raise quarter horses and travel constantly pulling a four horse gooseneck trailer. The truck has 195K and is original. It looks like crap, but runs great. The oil probably gets changed once each 10K or so, and they get it serviced at the quick lube places, so who knows what kind of oil they put in it.

That's our 5.4 story.