loss of power on top end

[kingbilly68]

It tachs up fine but just gets louder instead of faster. Happened this week while pulling a trailer from GA to WV. Start of trip, no problem gaining speed even in high gear. No down shift, just pulled the hills. By the end of the trip I could barely hold 65 and passing gear didn't gain any speed. Any help is appreciated.

[kingbilly68]

Btw, 2001 f250 automatic 136000 miles. Stock other than Cortex programmer...

[audiocontr]

See my signature.

[jesilvas]

Quite a few things to check.
How's the oil and filter? Recent change?
Fuel filter: when was last change?
Do you have any gauges?

[justinmix]

Louder like a whistling/rushing air sound? Off the top of my head sounds like a boost/exhaust leak. As the engine is under more load and RPM boost increases, which would make the sound louder. But if the PCM isn't seeing boost then it's not going to give it more fuel, so you have a low power condition.

I'd start with visually inspecting the CAC hoses and look for one that's torn or leaking. I'd also look at the exhaust manifolds and the up pipes at the turbo and look for any signs of black soot.

My bets on a boost leak somewhere.

[kingbilly68]

I did service around 2000 miles ago. Amsoil bypass filter and oil. New fuel filter also.

[kingbilly68]

Oil and filters changed 2000 miles ago. No gauges other than stock.

[kingbilly68]

@justinmix, thanks, will check those out today and re post later today

[justinmix]

Is that an accurate description? Is it a loud rushing air sound that increases with engine load and RPM?

[kingbilly68]

Not exactly. Kinda hard to explain. My first diesel...acts like it isn't getting enough fuel to keep up. Loses power in downshift at highway speeds. Has plenty of power on takeoff tho