I took my dual fueler off my truck and was left with an open fuel rail, so I got a fuel rail plug and I cant get it to seal. The plug didn't come with an o-ring so i threw one on and it was better for 30 seconds and blew out. And tightening the plug resulted in destroying o-ring. Any suggestions? I was thinking maybe a copper washer but im not sure. I dont have any of the fprv or associated items as dual fueler was on when i got the truck so the plug seemed to be the best route. Any help appreciated.