However my car petrol door/ cover has come off. It needs gluing back on. I have tried gorilla epoxy glue. But it keeps falling off. It's plastic that I'm trying to glue.
Surprised Gorilla epoxy doesn't work (contaminated with fuel so give it a proper clean with a solvent?)...still I'd still recommend JB Weld, that has never failed me. Not sure about uxing PVC cement, I suspect you're trying to glue together two different types of plastic with the door and frame.