Well lets see. I have a heavily modified 92 z28 Camaro. When i drive the vehical around for a while the fuel pump starts whining hard core. I take the gas cap off and a lot of pressure comes out and you can here the fuel tank pop and clunk like its blowing up like a soda can. When does the purge valve kick in?? Also the hot flowmaster is under the fuel tank.. Would this be the problem?? please help. I have also went through many diffrent fuel pumps. A autozone special ( when i had that and it would start whining it would almost like vapor lock) and now a ac delco which makes noise but never dies.

Thanks