Trouble with painted grill....

I just finished painting my factory chrome/black factory grill on my 08 tacoma. I researched it here and found numerous ways of doing it. I decided to use rustoleum bed liner, spray can. Of course I sanded it, then primed it with plastic primer, then it was sprayed with the bed liner spray. It seamed to crack, probably due to over spraying. I worked on that and waited for it to try and cure then I reinstalled it. On the way home from work it was chipped in numerous spots....What do you guys think? Did I use the wrong paint or should I put a coat of black spray paint to seal it?

 

No I just scuffed it up really good. Sorry about the post in the wrong spot. Just joined last week and it took me a while to figure out how to post and after I did I realized it was in the wrong section, crap....would it be better to resand it and then paint it? It's sticking to the black plastic, but not so well to the chrome...

 

You made two mistakes. First is most bedliner sprays do NOT adhere well to any plastics. They are great on any metal, bare metal or aluminum. Second as already mentioned you don't use primer when painting ANY kind of plastic, you use adhesion promoter in its place.