Did you notice the abs light coming on?
could be rear speed sensor??????
But something fishy here because Ihave never seen the tranny go into neutral when that happens.
If the washed the engine ,there may be water in the spark plug holes.
It will cause misfires possibly being your lurging,but that also could be your speed sensor.Compressed air blow out around all the plugs.
Take a look at it ,its mounted on top of the rear diff ,clean all the dirt away from area before loooking at it.
Rich