Will an extra letter in my name on my W-2 cause issues or delays when I e-file my tax return?

The extra letter should not cause a problem. When you enter your W-2 in TurboTax, below the employer information click "Show employee info." In the employee information enter your name as it appears on your W-2, even if it's wrong.

Do not change your name in the Personal Info or Your Info section. Your name there should match the name on your Social Security card.