I just bought my 2001 SCrew 4x4 with the 5.4 and 3.55 rear end. It now has about 4000 miles on it.
It is very snappy from the start and lower mid range. But when I am doing 60mph+ and try to pass or accelerate, it really seems to be having a hard time. I have to nail the accelerator and hold it down and at 70mph it doesn't seem to want to down shift out of overdrive.
I just got rid of my F250 PSD to get this. Is this the nature of the beast or is it as simple as needing to break in more.
Thanks for all replys and comments.
Cap

 

I have a 2000 150 with the same equipment you have....Put an exhaust system on it. That helped me out alot. Seems like the truck doesen't like to breath too well from the factory.

I hope that helps. It definately made a difference in my truck.

 

They do better after much more of a break-in; like over 10,000 miles. The exhaust???---yes, the factory 'garbage can' flows about 200cfms. Mine pulls off the line and just screams forward until the speedometer is pegged, and then some. There are no areas in any gear/speed/rpm that you feel "a hard time". It has always kicked out of overdrive when pushed very easily.

 

If you want your vehicle to drop out of O/D, just push the button. IT likes to stay in O/D for fuel economy and all that good stuff (thanks to typical american auto-trans calibration)

 

Thanks for all the replys.
I've noticed here lately it seems to be doing better. I guess it just needs a good break in.
Still dosn't have the power my old chipped Power Stroke had. That thing would scream on the highway at 60+mph.
Cap