I think the first thing I would do is remove the inside door cover and check the wiring. Although I could not find your unit listed in the recall Maytag has had a lot of problems with rinse aid dripping down onto the wires.

Next the capacitor
Capacitors can leak current and there is no way to check them at operating voltages without a special tester or bench setup.
It looks like it is relatively inexpensive ~$10.00..

Here is the tech sheet which I believe you have
http://www.servicematters.com/m...ibrary/docs/16023221.pdf

And a service manual
http://www.servicematters.com/m...ibrary/docs/16021814.pdf

Have you tried different cycle types?
Perhaps the turbidity sensor is doing something strange.

Also check the motor when it does this, if it is hot then it could be it's internal thermal cutout is operating.

The only other thing I can think of is the control board.
Perhaps the board is sensing a false high current and it may shut the motor down. They may have a built in software motor protect. Again this is just a guess because I cannot find info on how exactly the board runs. If you are getting a true high current then the motor should be hot.

With a little luck someone who has actually fixed this problem will jump in.