1997 ford e 350 v-10 stutters when accelerating. Smooth otherwis

Has the engine light come on yet?

It sounds to me like a passing gear issue. Or even and Over Drive issue. Try this to find out. When you put the car in gear, instead of O/D, try regular drive. If you have a push button O/D then deactivate it. If you only have Drive, then try shifting into 3. Run the car up to the same speeds you were having problems with. If you don't have the issues with the higher RPM's then it is an Overdrive/Highway gear issue. If it still stutters, then it could be a fuel delivery issue. Good luck.

Your TPS switch is on one side of the butterfly plate in the air induction system. Disconnect the connector to this part and hook an Ohmmeter to the TPS unit.

Then open and close the throttle by hand and observe the Ohmmeter action. It should be smooth to the throttle response. If it lapses and jumps, the TPS is bad.

Since you changed the sensor we will assume it is working. When you disconnect it you put the computer in limp mode which stops it from using sensor values. If code 300 is the only code we will assume the coolant temp sensor and others are ok.
I would check fuel pressure with a gauge next.

Fuel injectors may need cleaning.

First thing I would do is change the fuel filter and air filter

unlikely as faulty cat converters will cause problems under load and at rpm
check for fuel pressure problems and faulty u regulator not holding pressure over night

Have the throttle position sensor checked, might be faulty.

I would start with new set of wires & good plugs that should help.

sure, that could be it. I would also suspect the fuel filter as well.