Q: Carburetor backfiring and won't hold cold start.

Hi. It sounds like you are having some carburetor problems. Im going to guess you have a Holley or a Edlebrock. They both have been known to have many problems. I finally decided to get rid of my Holleys and obtained a Dominator, I have been relieved ever since. Your problem sounds like the needle and seat may have something stuck in them causing them not to seal off correctly. As a result, your fuel bowls are flooding the carburetor with fuel. At the same time, your choke might not be set correctly and may be stuck closed causing further flooding. I would recommend having a certified technician inspect what is causing your carburetor malfunction. Also, if it has sat for a while, you may be better off having the carburetor replaced by a certified mechanic to eliminate any further problems with your vehicle.