We have a 2007 Nox. @ 45 mph when the RPMs are around 1500 - 2000 the car will shake. Its kinda like the the rpms get stuck until you mash the gas. It does this alot. It has also started to do it around 60 mph. It doesnt feel like it is suspension related. Maybe a sensor. Has anybody else has this problem? And no check engine light. Thanks in adavance.