There is usually a huge different between my diastolic and systolic pressure (for example: 140/62). What could be the reason for this wide gap?
There is a phenomenon called the "pulse pressure" that can be a hallmark of aortic valve regurgitation. For instance, an ideal mean blood pressure of 120/80 has a gap or pulse pressure of 40 mm/Hg. So, at 140/62, your differential is about 80, which is borderline.
Have your cardiologist listen to your heart. Aortic valve regurgitation is not always heard on auscultation, so you can also request an echocardiogram to check your valve structures. I don't consider a wide pulse pressure to be indicative of coronary artery disease risk factors, but it may reflect leakage of the aortic valve.