Vapor Lock, how many have had this?

[DBLSPRT68]

Hello, I think I'm having a vapor lock problem on my truck. It dosen't do it all the time, but it dies when I'm pulling a load or putting a load on the engine. After it dies, and come to a stop , I switch my dual tank switch a few times, and she'll start right back up . I don't think it's the valve, because it's only a few years old and it's a GM part. I've posted more info on the engine & drivetrain board, but only got one opinion. Have any of you guys had something like this? This truck has been completely apart, and I don't have the charcoal canister even hooked up. Nothing is factory original anymore. Thanks, David