It is always a little nerve racking to go in with only the pre-approval and hope everything goes smoothly. it is also understandable given DCU declining your application.
It seems most people that have a pre-approval are good to go at the dealer. The dealer will have to do a final hard pull (you initially received a SP) to give you final approval. I am sure on occasion a deal does fall through but it seems many have no issues. The one thing I have read is that a few dealerships have tried to run the deal through other lenders saying they can get you a better deal. This seemed to be met with varying results but the rate should be what Cap1 advertised as well as the term and down payment if required.
You may also want to check out Carvana and see what you might qualify using their Soft Pull pre qualify (it would be a hard pull if you follow through). I would honestly stick to Cap1 as I like to see and test drive a car before it shows up!
Good luck and let the community know if you have other questions, lots of great people here to help!
