After 25 minutes of running, vehicle starts to lose power and run rough, like fuel begins to cut off. doesn't matter if your driving or in park. Vehicle runs/drives perfect for the first 25 minutes, until the temperature gets up to midrange, and has had a tuneup about 3 months ago. Checked the grounds, the vacuum lines, all connections, air filter is clean, MAF is clean, and we changed out the fuel filter, but nothing has helped.

Engine temperature?
What vehicle are we talking here?

Check the cap on the fuel tank as sometime they fail and wont let air back into the tank as fuel is used. The vehicle will run for a while hen cut out as a vacuum form in the tank After it has been stopped for while air leaks back into the tank it will start and run for a short time

suspect low fuel pressure to the injectors
run the fault codes to determine where the fault may be before you spend money

Begin with the basics......Start with a scan/check parameters

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The power steering works off the engine, so if engine not running, no power steering. It sounds like to me that a good place to start would be the fuel filter. If the fuel filter is plugged, it may allow enough fuel to go through to run the vehicle for a few minutes but not allow enough through to sustain continued operation. The fuel pump is also a consideration.

Sounds like the alternator has failed but without a good look i could say ,jump start vehicle then with engine running take a battery terminal off ,if it stops then the alternator isnt charging

First try and spray down the spark plug wires with some water from a spray bottom and see if the start arcing (you must have the truck running at all times to test this). If not that then clamp off the return fuel line and see fi anything vchanegs. let me know from there.

Check the fuel pump relay im not exactly sure where it is on your vehicle you could try looking inside the glove box behind a panal but it explains a lot of things you are discribing on chevys the pump will still work even if the relay is bad it is backed up through the oil pressure sending unit thats why its hard to start the oil pressure sending unit needs to build up enough pressure to trip the switch to power up the fuel pump and why you are having problems power loss its a fuel issue

Do a back pressure check on the cat converter if gas powered. Diesel doesn't have one. If you get 1lb or more psi of back pressure the cat is bad. Also check the fuel pressure with a gauge when this happens.

0340 is camshaft position sensor and the other 0325 is the knock sensor. Chances are you need to replace the sensors and good to go.