If I need to add a W-2 to my 2023 taxes and amend my return will this delay my existing refund?

[DMarkM1]

It is likely your original refund will be delayed.  The IRS computers typically catch returns missing an income source.  A letter will be sent notifying you of the discrepancy.  In the meantime you can prepare your amendment in TurboTax to add the missing W2.  Here is a link to assist as needed.