I got my '99 CEL checked at Autozone. It was P0455 - a large evap leak. The gas cap was on good and I haven't filled up in a few days, so I checked the evap lines over and don't see anything rotted or cracked. I guess I'll have to get it smoke tested. Can this wait a few days until I'm back in town and can talk to my local mechanic? Is there any harm in running with a large evap leak?