Just purchased a 1998 E450 V10 6.8 motor home and having some issues with getting it to run and idle. Has 23k original miles. Engine looks super clean. No leaks but having a issue getting it started. Well, I can get it started not will die when I let off the gas and try to get it to idle. Previous owner said gas has been sitting in it for about a year. Has new mass air flow sensor, and I can get it to run by spraying some starting fluid and cranking.

When I removed the doghouse I did notice this and it looks like this is off and not installed correctly. Any ideas? You can see the o- ring in the middle of the pic All help is greatly appreciated