when i start my 2000 ex coupe after it has been sitting for awhile. there is this sound coming from underneath the hood for the first 2 minutes. when she warms up, she is fine.

i dont think it is part of my exhaust. could it be something inside the engine like valves or something? kind of the a vibration noise.

80,000 miles on her.

also, today when i went to get gas and waited in line, she dropped in rpms sitting and idleing to close to 500 and started bogging slightly, first time she ever did that and she was fine after i left gas station...any ideas?