Hey there everyone! Just joined up and excited to be part of this community. That being said let me jump right in to my problem.

I just recently purchased a 2008 ford f350 5.4L gasser, supercab long box. The truck has 167,000km on it. I flew about 700km from my hometown to pick up the truck and drive it home.
After driving about 300km I started noticing a few problems.

The engine light codes that have been stored as of now:
P0420 (Catalyst code)
P0420 (Catalyst code)
P0191 (Fuel rail pressure sensor i think?)

The issue I'm having is that the truck has absolutely no power going uphill or accelerating. If I'm climbing a hill and have the gas pedal pushed in at a steady rate its almost as if the transmission wont shift, and if i push harder on the gas the truck begins to shudder. When the truck is cold it runs normal and climbs hills no problem, but once it heats up the problem returns. Another odd thing I noticed under the hood on my drive home was that they disconnected the vacuum line from the fuel rail pressure sensor and simply plugged the line on a random bolt.

Also, the truck apparently has a cam phaser lockout on it and I dont know if that could be causing the issue? Here's a list of some of the troubleshooting ive done so far.

-checked all fuses(start at the basics eh)
-checked resistance of coils(checked out fine, even after engine was warm)
-pulled spark plug 1 and 5, they both seemed fairly clean, not fowled up
-generally looked over all the vacuum lines, seemed fine couldn't see anything else really out of the ordinary
-while the truck was running I used a temperature gauge to see what the exhaust system was doing. On the drivers side when the truck was warm before the cat I had 140C and after the cat it was 80C(good indication the cat is plugged?) The other side tested fairly consistent.

Im hoping someone on here has maybe had the same problem or some great insight. They want $200 for the fuel pressure sensor not to mention new cats and I'm a little weary of starting to throw new parts on this truck without definitively knowing what the issue is. Please give me a hand here boys!

 

To me it sounds like the fuel pressure is dropping off which will trigger those codes and cause a lack of power.

 

The code 420 don't sound to good.
It's the Cats on Bank 1.
They may be melted and blocking exhaust flow.
That sure will cause a large loss of power.
The mod to kill/fix the VCT action has taken some of the torque away from the motor that it was built to have.
Sound like some ignorant hands have been working on the truck before you bought it trying to get around proper repairs..
Good luck.

 

Yes, plugged cat(s).