No acceleration on highway. Check engine light not on.

More than likely an intermittent *throttle by wire failure*.. Unfortunately the only way to prove that is testing while the failure is occurring... There is a throttle pedal position sensor that sends a signal to the throttle body position sensor as pedal is depressed, either sensor may fail 'intermittently' resulting in no accelerator pedal response .. Also possibly a wiring issue... There is no quick, push button fix, it needs to be tested.

I agree with pushrod. I would think any drive by wire problem would be an instant ck engine light and put the vehicle in fail safe (limp mode). Have you scanned the car for pending codes?

Pretty much its to get you home, the engine won't usually go very fast... (40 mph)... or so.