I have installed wings west door caps on my car and they keep pulling away around the top middle and front edges. I've tried using the thick double sided tape and it still won't hold. I've prepped it and it has new paint. Any ideas on how to get them to stay. They are urethane based.

 

Do you have pictures of it?
door caps, I assume 'door moldings'?
Do the door caps have a flat surface on the backside?
If its lifting from the edges and middle, the caps may not be flat.
Use 3M double sides tape and a heat gun to soften it up and get it flat on the door then just hold it in place till it cools down.
Alos make sure both surfaces are super clean, I use windex to prep and 3M double sided tape.

 

Lh mid
Lh front
Rh mid
Crx door cap

 

That was happening to my pathfinder trim due to age and I used the 3m plastic emblem and trim adhesive from autozone and it's still holding after a year!

Edit: Just saw that they are urethane, not sure if the plastic adhesive will bond or not.

 

Looks like the molding is warped a bit.
Use a heat gun to soften it up and then stick it on.