1998 Honda Accord code1456

Have 1998 Accord,aprox 120,000 miles. This car has starting issues. Occasionaly won't start when it does start runs rough. Engine Maintenance Light has been on for a while. Read on this site that a main relay could be problem. Anybody know where it is loceted on this model?

Also have retrieved code P1456 EVAP system leak, fuel tank system. Another friend's car had same code. It didn't seem to effect preformance, The car was identical model Anybody know what's up with this? Thanks.