We'll be in Sintra Sunday - Wednesday. Is it best to tour Lisboa on Sunday or would Monday/Tuesday be better. My husband wants to take the car in. Thanks for the advise.

Sunday would be your best day to drive into Lisbon since you won't be contending with weekday (worker) traffic. Personally I wouldn't drive into Lisbon, but rather take the train from Sintra. Traffic is very congested, roads are narrow, and parking is at a premium. Trains, buses and subways are easy to navigate and will be able to get you at (or near) what you plan to visit. That said, if you must drive, have a plan of what you want to see and find a place to park and use that as your base to explore beautiful Lisbon.

Take the train.

I would suggest checking out which days various attractions are closed and plan from there. It would be a waste to devote a day to Lisbon only to find out that what you most wanted to see was not open.