P1514/limp mode reduced power

One and only code rising to read both current and pending is MIL/SES/CEL "P1514- throttle body motor actuator."

Codes p0300, p0301 and p1514. So, new plugs, new coil, changed fuel filter, and cleaned the throttle body assembly. Same codes come back. Changed coils, cleaned throttle assembly. Changed oil to appease my own head.
Codes gone. Driving the test route and SES and reduced power kicked on, I rolled to the side of the road. Attempt to restart, a long crank and a spitting choked reluctant missing motor roared to life. It'll start and run and be smoother than I've ever felt at idle in Park or drive like a dream.
For a few miles, then out of nowhere. On a deceleration beep, beep, beep, the chimes tell me I have no power and we are limping.
If I clear codes with foot on gas WOT while clearing codes, I can operate the vehicle up until I take my foot off the accelerator, then the CEL other times I start it and its immediately reading an issue.

Things done so far:

Cleaned throttle body entirely.

Replaced spark plugs and coils.

Replaced two coils.

New alt starter and battery.

Cleaned all grounds.

Additives to stabilize fuel, remove water and all that jazz as directed.

New air filter
-teaced all wired to ECU and sensors. All connectors corrosion and bend free. Good contact assumed present. No change when wiggled.

God knows there's more that's pertinent. But I can't think right now. Please help me. I'm at a loss here and am not wasting another cent until i'ts logical.