Engine Knock when in Drive but not moving.

[aeidian]

If I'm idling and the car is in drive, I hear a knock, not a consistent one, or a specific pattern just random knocking. It'll knock once or twice, then nothing, then three times, then once, just on and off. If I'm in neutral it's fine, or when accelerating or at cruising speed it's fine too, it's only sitting still and in drive. Ideas?

[TheOtherNick]

Check the flex plate bolts.