The car was running fine,but
May be a bad ground to the relay,but the code for the bad ground to the e c m,most likely is the knock sensor,not plugged up ,or bad,or the o2 sensor is not grounded,or bad.Some times the e c m will go out upon removing and unplugging things,but I don`t really think,that this is the case.Check the oil pressure switch,it is in circuit for the fuel pump relay.It can cause ,an off,and on,start situation .But the e c m,no ground,usually means the e c m is gone out.Make sure of good tight connections on the knock sensor,and the o2,these ,if loose,can cause the e c m to go out,it doesn`t take much on a loose connection,to kill a computer.I hope this shed some light on the situation.If so,please let us know,thank you.