1998 Lexus LS 400 gas fill door

I'm assuming, when the cap release lever won't go back down, the fuel door also stays open. It sounds like the release cable is either dry or frayed. You can try lubing the fuel door latch mechanism with a spray lube of some kind in hopes this will work.This cable can be lubed, but it involves removal. With the amount of work involved in removal, you may just as well in stall new. Hope this helps.