My daughter came home from college and 90 minutes into her drive she lost ability to accelerate and got towed. We could not duplicate the problem and thought maybe she hit the shifter into manual accidentally. She just returned to college and approx 90 minutes into the drive she slowed down to 25 to pass through a toll booth and lost power when trying to reaccelerate.Engine would rev when accerator was pressed,but no power to wheels. She put the car into neutral and then back to drive and got it back. Any thoughts?

 

Check the transmission fluid level.

 

Doesn't this sound like limp mode?
No mention of any panel lights...but...

 

Not really because shifting to neutral then back to drive "fixed" the issue, if it was limp mode then you can only reset it by turning the ENGINE off and back on.

That's what makes me think this is a line pressure or torque converter issue. It also didn't throw a code for misalignment between the turbine input and output sensors though.

Plus actual limp mode (2k rpm limit and 5mph limit) doesn't cause the engine to rev freely without the corresponding power output, and your dash lights up like a christmas tree.

It's definitely possible the transmission just fell into neutral and she wasn't aware of it though, maybe the shifter just got bumped wrong and went into neutral without being FULLY pulled into the neutral gate, hence why she was still able to move the shifter further to the neutral gate then back to drive. It would have indicated on the dash what gear you were in though (it's controlled electronically not mechanically) and if it still said D while the engine could free-rev then there's a transmission issue of some kind.