[rblong]

I have a slight vibration on my 428 at idle (about 800 rpm). It isn't consistant. The engine had 6300 miles and on it when I bought it. I have put a few hundred on it since I got it and can't seem to determine what it might be. The vibration kind of comes and goes. No sound change, but you can feel it in the steering - not extreme, but your can just feel it every so often. Almost feels like belt flutter (as if you had a loose alternator belt), but the belt is not fluttering. As soon as your off idles it is smooth. Almost feels like a resonance vibration. All temps/pressure are great. Does it have something to do with being externally balanced? Any help would be appreciated.

I guess I should add I have not checked the obvious things yet like water pump bearings, alternator bearings etc. I guees I was tryiog to determine if this is usual to a 428.