Yep, same here, read all the reviews on how great the Icom IC-A6 was also. Very dissapointed with it when using it in the plane. Ignition noise and feedback were impossible to totally elliminate. My old Champ was non-electric and I took a 6-7 hour cross-country with this radio...nearly drove me nuts.
Works great for a carrying along while watching airshows/etc. but no matter what I tried I was not satisfied using it in the plane. Waste of money as far as I was concerned. Ended up putting my old King KX99 back in the plane for a back-up. Unfortunately it doesn't cover the newer range of frequencies.