Well if you are in 5th in the snow you are probably doing 50+ which might not be the smartest thing in the world. Or you are lugging the motor at too low of a RPM and its just jerking which any motor will do if you lug it too low. Or if you have a 99-up with traction control and it detects what it thinks is wheel slip its going to kill power momentarily which would account for it too. More details.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.