Engine/transmission fail, recover, restarted car then all good ... ?
 

On the way home in close to 100 degree heat, car is fully warmed up after 20 mins on the road and as I'm pushing on the gas, there's no forward movement (as if it's in neutral), then movement kicks back in, then drops off again, then finally no movement at all so I put on the hazards as I come to a stoplight.

The AC is still blowing so the car didn't shut completely off.
I shut off the car, restarted it, everything was fine for the rest of the trip (all of 10 minutes) back.
No issues on startup and battery is less than a year old so I doubt it's the battery.

Car has 225k miles on it, any ideas on what this could be?

So the car revv'd like it was not in gear even though it was? Were there any bad noises coming from the transaxle? There could be sheared teeth on the R&P gears.

Automatic or 5 speed?

Was the engine free-revving, or was there just no torque?

No revving, no noises. It's as if the engine shut off. But the weird thing is that it would come back, aside from the last time when I had to shut the car off and restart it and then the issue went away.

Auto

No revs, no torque

I thought you had a 951? Can you confirm we're even talking about a 944-series car here? I've seen you asking about other makes on this board before.

Disregard my question as I thought you had a 951 as well, and not an auto 944.

Thought it was an Audi or something, and there can be issues with transmission line pressure that can cause freewheeling. Probably a good story for an Audi forum that deals with that model.

-Joel.

2001 VW Jetta NA, principle is the same, just more knowledge on this board :)

sounds electrical perhaps gear switch or something in the sensor that tells the car what gear it should be in. had a friend with a 2002 jetta and he blessed his lucky stars the day he traded it in for a hyundai

I've heard good things but not 100% sold on the Hyundai.
I've helped a buddy with his Sonata and even simple things like changing lights are unnecessarily cumbersome.
Perhaps people are trading in old cars for newer Hyundais which make the Hyundai seem better but it's not a true measure.

What did you get when you scanned it for DTCs?