Its absolutely crucial that the front and back alignment is running true.....first thing to check is the corner to corner measurement, this will quickly tell you if the car is out of alignment.

Get the car on a nice level surface, with the front wheels straight, transpose the centre line of the tyre/wheel down onto the ground, push the car back and then measure the marks diagnally corner to corner, a couple of mm wont matter but it should if you do it acurately give you an idea of how far out the car is.....if its out after that i'll tell the best way to check and adjust alignment....

A car can measure fine alignment wise, but still be crabbing..


HTH

Ian