FJ60 2f Choking and stalling

[newindustar]

My stock FJ60 2f is choking and stalling, spewing black smoke and noxious fumes on cold startup after using choke. It won't idle at all when it is like this. Often turning it off for a bit and restarting and it runs completely normal and smooth. Sometimes it does not stop choking on itself even after warmed but then a restart or just keep driving and it clears and runs great. It is seriously ill then completely fine.

Could the choke mechanism be sticking shut in some way? How about one of the vacum controlled devices. I don't have any vacuum leaks and like I said it runs just fine once it clears up.

These is a big woosh everytime I take off the gas cap, don't know if it is in our out. Could the fuel system be getting pressurised somehow and forcing fuel into the carb?

Thanks