In 2003 I purchased a rental which was rented 100% of the time, and sold it in 2017. Can I deduct expenses from 2003-2008 when it was not on my tax return?

No, you cannot deduct past expenses on this year's tax return.

If you have omitted expenses from 2003-2008 when filing your tax return for those years, these deductions are now lost as you no longer amend your tax returns from 2003 to 2008. You can only amend your tax return three years from the date the original return was due.