Been there done that. It most probably not your pump but your cheap needle gauge. I threw mine out after I had the dealer come and check my new pump. It was fine. I then bought really good liquid filled gauges, end of problem.
Hope this helps
Fred

I would as Fred says, check the accuracy of the gauge and also check thoroughly for leaks.  The gauges can loose accuracy if impacted or dropped. 

A good guide is to listen to the change of the pumps tone as it achieves near full vacuum.  It should be a clear change. You can usually hear it more obviously if you shut the valve while the pump is working hard and see the difference.

If you are still struggling, then please get in contact and we will look further into it for you.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant