Honda Civic noise problem

I have a 2000 Honda Civic with 198,000 miles. Yesterday it started making a loud, fast-paced metallic noise when idling in drive and reverse, it goes away when I put the car in park or neutral, or when I accelerate. Other than the noise problem, the car still drives great. Any comments on the cause of the problem?

Maybe loose heat shield on exhaust system.

I had someone else tell me it might be a broken flex plate, which connects the engine crankshaft to the transmission torque converter. Does this make sense to anyone else? It’s going to be a few days before I can get the car into the auto shop to have someone look at.

A very common problem is the heat shield. A weld breaks on it and it rattles like all get out at low engine speeds.
Possibly you might be able to put a hose clamp on it, but other than noise it does not really harm anything.

You really want to check other things before you have the flex plate checked. Don’t fight us too much or it will cost you. Yes it could be the flex plate but it probably is not.

If you open the hood and watch the engine while someone else sifts the car between neutral/park to any gear, you will see the engine rock forward or backward. For this reason it may hit a loose heat shield under some conditions and not others. I think a cracked flex plate will make noise all the time. I’ve only seen one cracked flex plate and that was a long time ago, I don’t remember wether it made noise or not.