I have a 97 civic dx a problem, when I start the car when it's cold I get a lot of rattling in the engine but after a couple of minutes it's stops until I takes off then it has a tapping sound until it gets up to 30mph & once the engine gets to normal temp it stops & I don't hear it anymore, unless it sit still all day. Have taken the car to many shops but no one can tell me what it is, have had valve adjustment, timing belt changed, tune-up but it's still there.