I have a few questions about the car before I get to work tomorrow...

1. Best oil weight? Live in South Carolina.
2. Best spark plugs? I purchased some Autolite 606 at Walmart on sale, will they function correctly, are they one heat range colder? Or should I just get the 605s? I have no modifications on the car.
3. Any other tips on why my air vents aren't blowing at full capacity? I did the EVAP clean.
4. My check engine light comes on randomly, usually when slowing/braking to a stop. Brake fluid is full...
5. Coolant flush, is there a way to determine if i have dexcool already in?

thank you

Welcome to the forum. I'll try to answer some of these.

1) Stock oil is 10w30
2) I believe the 606 is a copper core which is the kind you want without any modifications to the car.
3) Not sure about your vents
4) You can check the code stored without a scanner. Info is in the tech info section
5) Dex is usually orange and regular fill is greenish color.