Fuel Pressure Too High Code

[Silverwolf]

High everyone. New to the forum, need some help with my 06 ISX 400. It threw a code for fuel pressure too high. (128 94 0 code) I can't figure out what would cause this, and its causeing a huge loss in power. It drives fine, runs fine and smooth, but it only has about half power. It throws the code every time I start the truck, then won't do it again until I start it again. But the power loss is all the time since the first time it threw the code. Can anyone help me figure this out. Its the only way I can move my backhoe, and I can't afford a mechanic.