When I was working on my SC return the other day there was a place for Car maitinence expenses. ( Gas gallons, oil change). I now that I am on there today i dont see it

Actual car expenses are entered on your Sch E rental or Sch C business in the federal section.

Can I switch between the standard mileage rate and actual expense method?

Actual Expenses - To use the actual expense method, you must determine what it actually costs to operate the car for the portion of the overall use of the car that's business use. Include gas, oil, repairs, tires, insurance, registration fees, licenses, and depreciation (or lease payments) attributable to the portion of the total miles driven that are business miles.

Note: Other car expenses for parking fees and tolls attributable to business use are separately deductible, whether you use the standard mileage rate or actual expenses.