Ahoy dayman ---
Low and left is a very common shooter error.
Its all about maintaining sight picture and imperceptible trigger pull, and learning to do this very quickly. This is why SA shooting is so much easier than DA (for me), and the trigger on a 1911 is unparalleled.
In the short term you can cheat by shooting 2-handed, ie using the support hand to gently nudge the bottom of the trigger guard. There is an easy way to do this but hard to describe.
You're shooting decent groups already, so you will get there...I'm sure I could get you to 1-1.5" groups, center target in 15 minutes or less.
Get some snap caps and do like hornet41 & JimPage advise. Become one with the gun. You will get there, Jerry Miculek said it took him a gazillion rounds to learn what he knows.....