I had a service engine light on for a while so I decided to look more into it as I'm due for a new plate sticker. I had a code P0442 so I decided to look over the car for issues. The only obvious problem I found was that the shroud clamp on the air intake was very loose to the point that it was ready to fall off. I tightened it and reset the computer and it's now day two and the light hasn't come back on. I don't believe that this has anything to do with the evaporative system but the computer seems satisfied. How long is it before the computer runs it's coarse so it's safe to go in for a test ?

If you check the Drive Clean website it explains what you need to do to make your car ready if your engine control system has been reset.Download the brochure"Why wasn't my car ready for its Drive Clean Test"

It describes the "drive cycle" you need to complete so that sufficient data is stored to pass(or fail!) the test.

Thanks I didn't realize the AC was required as well, I will do that in the morning before the test.

For those in the USA, Go Ogle for your particular State's Emission testing web pages and run through the 'FAQ'.

Rather 'generic', but it does cover the specific plan you will be facing, and your taxes have already paid to produce the information so..

As an example, those on OBDC II for Virginia are here:

Virginia DEQ - On-Board Diagnostic System FAQ

Virginia DEQ - Understanding OBD Monitors

Bottom line? If there are flaws, one gaineth not by slapping a 'clear code' at everything in memory the morning of the test. All the needfuls must be cycled again anyway.

My car passed with no issues, good for 2 more more years