I am thinking of buying a used 97 vw golf. the car has only 97000 kms on it. I took it for the emissions test and failed. The car passed all parts except the NO ppm. the limit is 605 for the car and the machine read 866. I had the oil changed just before i took it in for test. the car has only done about 5000 kms the last year. what should i have done to prepare better