A member of the public saw him leave the car with a beer bottle in hand, ''unsteady on his feet''.
They called police, who found the defendant at home, where he admitted the offence and said he was ''just dropping a friend off''.
Coward was unable to give a breath sample so was required to provide blood for analysis.
The result was 249mg of alcohol per 100ml of blood - nearly five times the legal limit.
Just 18 days later, a police officer had stopped in Rockyside Tce and was filling out a court summons for the incident.
A passing car caught his eye.
It was Coward, driving the same Toyota as on the previous occasion.
He was pulled over in Lindsay Rd and the police's suspicions were confirmed.
The officer approached the defendant to give him the documentation from the August 5 incident when they noticed signs of alcohol consumption.
A breath test gave a reading of 596mcg.
The legal limit is 250mcg.
Defence counsel Len Andersen accepted his client had a ''horrendous list'' of convictions, nearly all of which were for drink-driving.
''Clearly, he has an alcohol problem,'' Mr Andersen said.
But Coward said he had abstained since the double indiscretion and was motivated to address his issues.
Judge Macdonald noted the defendant did not have a history of driving while disqualified or breaching other court orders.
Coward was banned from driving indefinitely and ordered to pay $216 for the blood analysis.
