I have a 99 250 4x4, it had 168,000 on it when I bought it. At 171,000 I ended up changing the motor (broken ring). It use a quart of oil every 500 to 1000 miles. With my new engine it started out good but when I drive it hard (65-90mph) on long trips it went back to using 1 qt every 1000miles. Now that I have been back in town no oil use.

Orignal engine vavoline 5w30 to syn pensoil 5w30. Syn made it worse.

Now nothing but motorcraft 5w30. 181,000 on truck, 45,000 on engine.

 

i just switched to amsoil 0w-30. ran 5,000 miles - and it was down a quart. just returned home from 1,200 trip and dropped filter and added about 1.5 qt. i'm a little skeptical regarding the drop and add routine, but may return to mobil 1 0w-20, with changes every 3,000 or so. it is my understanding that some oil consumption is normal, as oil should get "lost" in the valve guide assembly and other internal parts so that it is doing it's job lubricating. cheap insurance...

i swear by synthetics, particularly with additive packages...

 

I'm lucky with my v10, no measureable oil useage in 5000 mile interval with Mobile 1.

My old 150 with the 5.4 used oil like crazy. 1000-1500 miles per quart. Ran Auto-RX and it reduced to 1 quart in 3000. By the time I was done with the rinse cycle it was 1 quart in 5000.

Maybe your rings are dirty and seized, or glased cylinders. I don't think my 150 ever broke in.

Eric