The Dreaded Drive Clean Test
There is really no need to study (or go to great lengths in pre-test maintenance) prior to a Drive Clean test.
If your car starts easily, runs smoothly and gets reasonable fuel mileage you’ll probably pass the test. should your car fail, at least you’ll have an idea of what it needs and time to address it. A retest is only $17.50.
As far as getting your car as hot as possible prior to the test, don’t. Most cars will pass the test at normal temperature and as a matter of fact, some models (those without an EGR valve) may fail the NOx portion of test due to excessively high combustion chamber temperature.
A smile during the test will always help.